IMSAblog

1976 : Al Holbert's first title

1976 was the year the Chevrolet Monza took off. Its development had been fulfilled and the car became a true winner. It was not to happen before the Atlanta round however.
The first race : the 24 Hours of Daytona was won by BMW who did win a very strange race. Grand National cars were allowed to run the race and the overall purse was $100000. Peter Gregg, Brian Redman and John Fitzpatrick won a race that was stopped during 2H40 when the official discovered water in the gas. The time spent in the pits was used to purge the circuits and some teams made extra repairs on their cars. The BMW had a comfortable 17 laps lead which permitted her to keep her advantage as it ended the race at a very slow pace.
Next race, at Sebring, was a race that nobody seemed willing to win. Hour after hour, each leader was stopped by some incident. John Greenwood had once again won the pole, and set a new track record. At the start, Greenwood took the lead during 15 laps. Just before the end of the first hour, he unfortunately hit a backmarker : he came back to the pits for lengthy repairs and was soon withdrawn from the race on the 36th lap. Then David Hobbs would grab the first place and hold it until the 63rd lap. But the car suffered technical maladies and Michael Keyser then was able to take the lead, but he was soon hit by another car. He pitted for some repairs on his damaged exhaust pipes. A new Porsche Carrera had taken the lead, it was Jim Busby-Carl Shafer car. They led the race until midway point. Their advantage was about one lap over Bob Hagestad-Jerry Jolly car when they lost a wheel on the course. Bob Hagestad-Jerry Jolly took the lead, they were just ahead of Al Holbert-Michael Keyser car, two laps down. They were to be stopped by an electrical problem, and relinquished the lead to Holbert's car. The BMWs had been slowed down by mechanicals, and Al Holbert-Michael Keyser won the race by a two laps margin over John Gunn-Carson Baird in another Porsche Carrera. The first non-Porsche car was Peter Gregg-Hurley Haywood, on their BMW 3.0CSL, who finished strongly to take seventh. The GTU was won by the Porsche 911S driven by David McClain-Dave White.
Next race was held at Road Atlanta, a 100Miler. Al Holbert was christening his new Chevrolet Monza. He had to face a strong challenge by Michael Keyser, who ran a similar car, and won his first race with the Monza. Second was Michael Keyser and third Peter Gregg on his BMW 3.0CSL. Michael Brockman was fourth in his customer Greenwood Corvette. Eight Monzas took the start of this race! Brad Frisselle won the GTU class in his Datsun over Dave White, driving a Porsche 911S.
Laguna Seca saw another Holbert victory. He finished just ahead of Peter Gregg, Michael Keyser was third.

Michael Brockman at the wheel of the Team Levitt car at Laguna Seca

Photo courtesy Greenwood Corvettes

At Ontario,  Jim Busby won a wild race over Peter Gregg in his Porsche Carrera. In fact, he was fighting hard with his boss and sent him spinning on the last lap to win the race! Third was George Dyer on a Porsche Carrera too. Walt Maas took the GTU category on his Porsche 914/6, second was Jim Cook on a Porsche 914/6 too, Brad Frisselle was only fourth, and Bob Sharp was third in the GTU class.
Lime Rock was the closest race of the season as George Dyer won over Michael Keyser with a one thousands of a second margin!  Brad Frisselle was back in the GTU winners' circle, and won over Walt Maas.
Mid Ohio saw a reversal of the roles as Michael Keyser won the race over Al Holbert. Jim Busby was the hero of the race as he took third place after starting 31st and working his way through the field. In GTU, it was again Frisselle-Maas for a one-two show.
The Paul Revere 250 at Daytona was a night race and Al Holbert won again over George Dyer and Peter Gregg. Brad Frisselle won over Rusty Bond Porsche 911S in GTU.
The next race was held at Sears Point for the first time. Jim Busby dominated the qualifying sessions. He easily won the race, again beating George Dyer and Peter Gregg. Al Holbert started 47th and finished 4th. Walt Maas won again in GTU, edging Brad Frisselle for victory.
At Talladega, bad weather ruined a very special race and Peter Gregg emerged as the winner. Second was Phil Currin who scored his best result of the year in his Corvette. Bob Christiansen finished third in a Camaro. Brad Frisselle won over Dave White on a Porsche 911S in GTU.
At Pocono,  Al Holbert won again to stretch his points lead. Peter Gregg was second and Elliot Forbes Robinson was a surprising third overall driving a Bob Sharp Datsun 260Z. He easily won the GTU class.
At the Mid Ohio 6 Hours, turbocharged cars were to be allowed for the first time. Jim Busby ran solo to win the race over Peter Gregg-Hurley Haywood on a BMW 3.0CSL. Al Holbert finished third. Brad Frisselle-John Morton finished fifth overall to easily win the GTU class. George Follmer-Doc Bundy were fourteenth overall on the Dickinson backed Porsche 934. Another Porsche 934 was driven by Paul Miller who took twentieth.
At Road Atlanta, a 500km race, Al Holbert won over Jim Busby and Michael Keyser-Jim Trueman took third place. Charlie Kemp was the fastest qualifyer on his Ford Cobra II. His car seemed to have gained a new reliability and was now a serious contender for the win. Brad Frisselle-John Morton won the GTU class over Rusty Bond-Ren Tilton Porsche 911S.
The next race at Laguna Seca, for the second time of the year, saw another victory by Jim Busby, driving his usual Brumos Porsche Carrera. Second was Peter Gregg and third Hurley Haywood on a Porsche 934. Michael Brockman was fourth on his Corvette. The GTU class was taken by Walt Maas in his Porsche 914/6 over Jim Cook in a similar car. Brad Frisselle did not enter the race. Al Holbert, Peter Gregg and Jim Busby posted a great fight from the beginning of the race. After each of them dropped from the top spots, Michael Keyser took the lead and won the race over Charlie Kemp, in his vastly improved Ford Cobra II, and Danny Ongais on a Porsche 934. The latter who soon become one of the most prominent figures in IMSA racing for the next years. The GTU class was again won by Brad Frisselle, who finished ahead of Elliot Forbes Robinson's Datsun. Al Holbert won his first title on a Chevrolet Monza, and it was the first time that an American manufacturer would win a major international series. Brad Frisselle easily won the GTU title, posting eight wins on his Datsun 260Z. Walt Maas was the runner-up, taking four wins in a limited schedule.

Corvette GTP : America's hottest weapon

In 1982, Vince Piggins, director of the Chevrolet Motorsports Group, initiated a program to develop a GTP car. He had worked with Interscope Racing, which was headed by Ted Field, as Chevrolet had developed a relationship with Lola Cars. But Chevrolet wanted to run its own cars and they needed to develop a Turbocharged engine. As it was the standard for GTP racing, it was obviously the way to go. Then came Ryan Falconer, an engineer who had worked on Chevrolet V8s for road racing for many years. He started building engines in 1963 for the Lola GT cars that did Le Mans that year. He saw the potential for building a Turbocharged V6 engine that would be installed on a Lola T600 chassis. But Lola did not accept so he went to Ted Field, who accepted and ran it for the 1982 Daytona Finale. The car had a V6 3,4L twin turbo engine and was an absolute rocket, but retired from the race. Subsequently, IMSA banned twin turbo cars. The switch to a single turbo engine could be easily done, but Interscope suddenly quit racing at the beginning of 1983. Falconer's motor was a 3,4L single turbo V6 with cast iron block and aluminium cylinder heads. The single Warner Ishi turbocharger unit produced 700hp at 8500rpm and Ryan converted the Porsche injection to go on it. At that point, Chevrolet was working on a body that would fit the Interscope Lola chassis and designed one that would retain the Corvette general look. Randy Wittine was to design the new car. The new car was assembled in Great Britain and the development was completed until the car was to be seen at the 1983 Detroit Auto Show. The new Turbocharged car was the T710 and its normally aspirated cousin the T711. The two cars would be legal for both IMSA and Group C Championships. In fact, seven cars were to be built by Chevrolet, all based on the Lola chassis. At the beginning of 1983, choices were to be made by Chevrolet considering the opportunity of fielding a GTP car.  In 1984, Danny Ongais was interested but the project was put aside during one year following an argument between him and Chevrolet.
With a non-extensive budget, Chevrolet decided to put this project on hold. Ryan Falconer, sensing the fact that he would have to wait for a long time before Chevrolet would go ahead, arranged a test session at Laguna Seca with Jim Chapman and John Bright. The latter had worked with Brian Redman on the Lola T600 project. He called some of his friends to test drive the car. They were Al Unser Sr and Al Unser Jr and Mario Andretti. The car proved extremely fast but was easily burning into flames!  In fact, the main problem was cooling. Some major changes were made, and Lola would then improve its car. Chevrolet was not willing to race the car, so who could do it? That really was a problem because Ted Field now was out of racing. The other team that Chevrolet could have chosen was Blue Thunder Racing, the 1984 IMSA Champions, but their source of funding was quite not clear. In fact, the debuts of the Lola T711 was made by Lee Racing, a team owned by Lew Price, a man who has made his money with Lee Metals. He bought the chassis for $140000, it was fitted with a 5 7L V8 given for 550hp. The car had Firestone tyres, the reason for this choice was to give the manufacturer a chance to make a comeback in motor racing. He had run small sedans and hired Carson Baird as a driver. The car made its racing debut at the 24 Hours of Daytona 1985 where Baird qualified 13th. It was a dnf for the race after 53 laps. For the next race at Miami, Carson Baird and Chip Mead finished at a honest 7th overall. Sebring was another dnf after starting 9th. Baird was a multi-purpose man : he acted as team manager, chief mechanic and driver. It was not a factory effort, but Baird and Price met with Chevrolet engineers several times and got assistance from them. The car suffered several problems throughout the season. During the 1985 season, many funded drivers paid for their rides, and Lew Price could pay his expenses.

Chip Mead drove the Lola T711 at Columbus and did not finish.

Copyright Mark Windecker

The car was to be run just a lttle more than one season. Then Lew Price sold his company and was later killed in a traffic accident. The car was sold to a private collector and never raced again in IMSA.
The Lola T710-01, fitted with a turbo V6, was run by the Rick Hendrick Team. A successful NASCAR Team owner, John Pierce had arranged the deal with the ex Kreepy Krauly team. David Hobbs had tested the car in the summer of 1985, and GM decided that the car would be fielded by this new team. The car debuted at Road America in 1985 with David Hobbs and Sarel van der Merwe, a south African driver.

The new Corvette GTP(Lola T710-01) on the grid at Road America in 1985
Copyright Mark Windecker

It was a dnf after qualifying eleventh. The car did not appear as a potential winner until the last race of the season, at Daytona. It started from the pole with van der Merwe driving. He was partnered by Bill Adam. The car did not finish the race, and suffered an engine failure. Chevrolet became aware of the car potential, and hired more people to work on it. For 1986, two more chassis were built and Doc Bundy was hired as van der Merwe's co-driver.  At the Daytona 24 Hours, the car took the pole but did not effectively take the start of the race after Wally Dallenbach Jr felt a vibration that could not be fixed. The first victory came at Road Atlanta after claiming the pole. Unfortunately, the car was destroyed at Riverside in a memorable accident involving Lyn St James, Chip Robinson and Doc Bundy. The new car was plagued with overheating problems but a new win was registered at West Palm Beach in June. Two other cars, designated 8612, were built by Lola and they were quite new cars, with new features. They had 17inch wheels, an active suspension designed by Lotus. The first of these two cars was raced at Columbus, but retired as well.
In 1987, the two cars claimed four poles but did not win any race. A second at Laguna Seca was the best they could do.They were outnumbered by the Porsche 962s.

The car did not start the race at Columbus in 1987. It was driven by Sarel van der Merwe and Doc Bundy

Copyright Mark Windecker

In 1988, they could do no better than a third at Watkins Glen. Their final race was at Del Mar. Bobby Rahal came up in fifth and Sarel van der Merwe was a dnf. Then the cars were taken back to Indianapolis. These cars would never be seen on a racetrack anymore. GM had plans for building a brand new car. Paul Brown was to design it and a special attention should be given to cooling. All of a sudden, Chevrolet decided to completely abandon the GTP program, and there was no more any race team. Hendrick kept his two cars but one of them was finally destroyed as a pile of remains.
Peerless Racing did make the move to GTP racing in 1988 and purchased the last Corvette GTP built by Lola. Jack Baldwin and David Hobbs drove the car for the three last races of the 1988 season. Their best result was a fourth at Columbus.

Jacques Villeneuve drove the Peerless car at Mid Ohio in 1989 and did not finish the race as per usual.

Copyright Mark Windecker

Jack Baldwin just considered this car as the worst he had ever driven. This car could be seen in 1989 with Jacques Villeneuve at the wheel but with no consistent results.  It was the last time a Corvette GTP would be seen on the IMSA circuit. The Corvette GTP had just ended its stellar career and was not to be seen anymore.

Charlie Kemp Cobra II

Charlie Kemp was an experienced racer. He had run Corvettes and Mustangs as well as Can Am racers. At the end of 1975, he met Mark Donohue for a speed record tentative. Mark was negociating with Dekon Engineering to field a pair of Monzas for 1976. Unfortunately, Mark Donohue was killed later in the season, and Charlie Kemp lost the deal to Al Holbert. Undaunted, he found out another way to break the German cars dominance. He decided to switch to the Chevrolet Monza lookalike car : the Ford Mustang Cobra II. The AAGT category was the perfect way to go for such cars. So he decided to go this way.
The car has been built by Ron Fournier and the engine came from Gapp and Roush. The 351ci engine gave 560hp which was more than the Chevrolet powerplant. Bob Riley designed the chassis and body panels. The suspension setup was rather conventional, with unequal A-arms up front, a live rear axle and coil springs over shocks all around. Kemp's racer used Hurst-Airheart disc brakes. Wheels were 12X15-in at the front and 17X15-in at the rear. The car was very low, and looked rather slick. Unfortunately, Ford was not interested in the project, even though engineers sometimes went to Ron Fournier's shop in Royal Oak, Michigan. Very optimistic, his goal was to bring to the front the former "Chevrolet-Ford" wars.
Back in 1976, the car debuted at Daytona for the 24 Hours race. Very radical in its design, the car was not accepted as an AAGT car! His car was moved to the Le Mans GTX category. The exhausts were inserted in the doors which were bolted and thus could not be opened. Aerodynamics has been one of the key point in the development : the front piece of the car has been thoroughly redesigned. As the season went on, the car had to be constantly updated in order to meet IMSA's requirements. However, the car improved and was later fitted with an Australian motor. This powerplant was more powerful, and was given for 635hp. At the Daytona Finale in 1976, Charlie Kemp wound up his best result with the car and came home with a second place overall. Very fast, Charlie Kemp was clocked at 212mph on the banking.

Charlie Kemp at the Daytona Finale in 1977

Copyright Dave Kutz

As years went by, the car was evolving but never won any race. It could be seen until 1980, at the Daytona 24 Hours, there, it failed to qualify the race, and the race direction excluded the car from the competition It was the last time the Kemp Cobra II was to be seen on a racetrack.

12 Hours of Sebring 1983 : a surprise winner

The third race of the 1983 Championship was to take place, as per usual, on the Sebring circuit. An old airfield which was used since 1973 by the IMSA Championship. Yet, it always has been one of the most popular race of the season. For this race, the track has been modified and had lost 0,44 mile. The very extreme part of the track had been deleted and a brand new section was to be used by the racers. What's more, the road had been entirely repaved, which was a good thjng, from the racers point of view. The Sebring spirit remained the same with a lot of extra-race action. Many spectators were there not only for the race but to spend some time watching cars while drinking and having a good time : that was Sebring. The entry for this year was plentyful but potential winners were not to be more than nine or ten cars. It was essentially the Jaguar XJR5, the single Lola T600, the two March 83Gs and the 82G Porsche powered, and the four best Porsche 935s, plus the unusual Grid S1 Cosworth. The other cars could not hope victory if the best cars proved reliable. But on such a track, everything remained possible.
87 cars would take the green, which was a record for this race. But many old cars would take the start, and quantity did not make quality, it was an obvious fact for this very race, but it would make any spectator happy. The different practice sessions were splitted by category, and the last one would be run by every car in a free running session. At the end, it was John Paul Jr, who had been hired by Preston Henn, who took the pole in 2m23s965, just ahead of a surprisingly fast Jaguar XJR5, who did 2m25s590. Third was John Gunn, on his Phoenix JG1 Chevrolet, just a little bit behind the Jag. This homebuilt car proved quite fast but the reliability was really the problem. Fourth was the March 83G Chevrolet driven by Marty Hinze-Randy Lanier-Terry Wolters and the single Lola, driven by Ralph Cooke-Jim Adams and Josele Garza. Two Porsche 935s took the sixth spot, the Bob Akin Coke car leading Bruce Leven's one, driven by Leven himself, Al Holbert and Hurley Haywood, a team that you could not underestimate! Then, Pepe Romero's pink March 83G Chevy driven by Doc Bundy and Bill Whittington, the second Swap Shop car, the Grid driven by Milt Minter-Skeeter McKitterick was tenth and this car led the first GTO car : the Stratagraph Camaro driven by a fantastic Gene Felton. He was no less than six seconds ahead of eventual winner Wayne Baker, on his Porsche 934! A pair of good Oftedahl Pontiac Firebirds, a very fast Mazda RX7 and a bunch of Porsches, Corvettes and Mustangs would make for the huge field.  The GTU category was led by John Casey's Mazda RX7 driven by Joe Varde-Jack Baldwin and John Casey. Two other Mazdas followed, the Kent Racing car driven by Lee Mueller-Terry Visger and the Mandeville car, driven by Roger Mandeville himself and Amos Johnson-Danny Smith. The next car was the BF Goodrich Porsche 924GTR driven by Paul Miller-Jim Busby-Ron Grable. Plenty of close racing should have to be seen in this category.
A lot of very old cars were allowed to make for the start, such as a Ford Capri, a Renault 12 and a BMW 2002. That was racing in those days.
The start of the race was to take place at 11am. A fine weather was there to welcome a big crowd in the early morning.
At the start, the Jaguar jumped in the lead but she was soon overtaken by Bill Whittington driving Pepe Romero's pink March 83G. Pushing hard, he extended his lead over the British car to 30 seconds at the seventh lap. He would go no further as the transmission let go on the next lap. He knew that the car would not survive so he did explode it. The Porsche 935L driven by Derek Bell did not run strong as handling did not seem to be allright and turbos lost pressure. He would stop to get his problems fixed and was eleventh at the end of the first hour. Don Whittington then hit something on the track and would lose a lot of time in the pits for lengthy repairs. The Stratagraph Camaro hit the wall too and would lose two hours. It would be obvious that the section of the track was quickly fading and pieces of tarmac were getting torn away as cars passed by. Soon, the race direction would decide to have the race stopped. The pace-car was out and wiping cars would clean the track. The race was off for 43 minutes. The Jaguar had taken the lead of the race but she had put up a good fight with the Bayside Racing Porsche 935. It would last until the end of the fourth hour but the Jaguar would be stopped by a broken head gasket. The Porsche 935 driven by Al Holbert-Hurley Haywood would soon have a clear race of its own. The Lola T600 driven by Ralph Cooke had a tyre burst and broke oil lines, the car was badly damaged. The Grid had to stop to change the front end and the Preston Henn's Moby Dick 935 was to be stopped at regular intervals, running fast between two pit stops. Running smoothly, the leading car was soon hampered by small problems. A broken body prop and a gearbox failure. Lying in ambush, two cars were soon fighting for the lead. The Coke machine driven by Bob Akin-Dale Whittington-John O'steen and the March 83G Chevy driven by semi-pro drivers Marty Hinze-Randy Lanier-Terry Wolters. Those two cars would swap their positions on every lap and captivate the crowd. But luck was not to be on the March side as a stone would soon bore its radiator. The car would retire quickly after the engine broke. The Porsche 935 driven by Michael Andretti retired at the same moment. The Bob Akin Porsche 935 was a clear leader at this moment and was two laps ahead of the fantastic Racing Beat Mazda RX7 driven by Rick Knoop and Pete Halsmer. The Bayside Porsche was third overall but this car was now constantly slowed down by electric problems. The Grid was working  its way to the top spots and was a clear fourth. After ten hours of racing, the Coke Porsche was always leading the race. Dale Whittington took the wheel but suddenly could not restart the engine. Losing more than half an hour, the mechanics would soon discover that water was found in the gas. That same incident that took place at Daytona in 1976 and, all of a sudden, panic would spread like gunpowder. Meanwhile, a small car had just taken the lead of the race : the Mazda RX7. The car was running a constant 2m52s per lap but losing a clear 10s per lap on the Grid and the Bayside Disposal car. The Mazda drivers did believe in their chance to win and were pushing hard. Unfortunately, Pete Halsmer would spin at the Camel hairpin and damage his left-rear wheel. Coming back to the pits, his mechanics would do their best but the car had suffered too much, it was a retirement for the valiant little car. The Grid was now in the lead but began to experience handling troubles. Haywood-Holbert were closing on and, with one hour left, no one could guess who could win the race. But the two cars would surprisingly stop many times for minor checkouts. The Grid was having its front-end checked and the Porsche was having its lights fixed. A wheelnut would definitively stop the Grid. At that moment, Bruce Leven was reasonably thinking about a new victory, after the '81 one. Then came the Porsche 934 driven by Kees Nierop-Jim Mullen and Wayne Baker.

The Porsche 934 driven by Wayne Baker-Jim Mullen-Kees Nierop was a surprise winner of the race

Photo copyright Mark Windecker

Running very constantly from the beginning of the race, it was now in second position. As the leading car did not have its lights working correctly, the Porsche 934 finally took the lead as the Bayside Porsche stopped again and again. This car would finally lose the second place to the Coke machine, who had finally his water in the gas trouble resolved. Dale Whittington had stormed back to second place but was aiming at victory. But his effort was not to be rewarded by luck as, when the chequered would fall, he would be still 1m34s down the winner. This car was a complete surprise winner and was, to his owner Bob Garretson, looking like a revenge. Jim Mullen, Kees Nierop and Wayne Baker were the greatest upset victory of those glory days. The Porsche 935 was winning the GTX category and a Mazda RX7 won the GTU class with Jack Dunham-Jeff Kline-Phil Compton just ahead of Joe Varde-Jack Baldwin-John Casey similar car.

1977 : the coming of the turbos, part 1

That year saw a great change in IMSA rules as turbocharged cars were allowed to compete in the growing Championship. John Bishop admitted that he had no other choice but doing so. The Porsche 934s were not exactly what they used to be in Europe and featured group 5 bodywork with shark wings and bigger tyres. BMW entered a new car : a 320i powered by a 2,0L turbo engine. Driven by David Hobbs, the car showed a great potential but suffered from reliability problems. At the end of the season, it was Al Holbert who clinched a second title in a row. He drove an improved Chevrolet Monza which proved a potent car. Featuring a huge rear wing and extra aerodynamical mods, he won four races out of fifteen and took four second and one third to beat Hurley Haywood by a mere seven point margin.
The season started with the 24 Hours of Daytona which were part of the World Championship for Makes. A bunch of European competitors did make the expensive trip from Europe and added a welcome diversity to the usual IMSA field. As was expected, the works Porsche 935 did prove to be the fastest entrant with Jacky Ickx and Jochen Mass at the wheel. But the Kremer car was not so far and with Bob Wollek driving, you could expect some stiff competition. The fastest IMSA car was the Brumos Porsche 934 driven by Jim Busby and Peter Gregg, they started seventh just ahead of Al Holbert-Claude Ballot Léna-Michael Keyser Chevrolet Monza. The beginning of the race saw a domination of the Works Porsche 935. It was vaguely contested by the Porsche Carrera Turbo driven by Danny Ongais and George Follmer. But this car was rapidly out of contention after 65 laps with a blown piston. After three hours, Jacky Ickx-Jochen Mass were in the lead but later, Jochen Mass would have a tyre burst on the banking. Coming back to the pits, he would lose a lot of of time and their car would drop in the standings. Bob Wollek would take the lead and the Martini Porsche would carve its way back to the top. They were back in second position by 6.30 when Jochen Mass again damaged his car on the banking, this time definitively. Bob Wollek and his codrivers held the lead until 11am but were soon forced to pit with a broken rear hub. They lost thirty minutes and were overtaken by the Porsche Carrera RSR driven by John Graves-Hurley Haywood and Dave Helmick. The car proved quite reliable and would retain its position until the chequered. Second was the Italian Porsche driven by Martino Finotto-Carlo Facetti and Romeo Camathias. Bob Wollek-Reinhold Joest and Albrecht Krebs finished third. 
Next race at Sebring saw a huge field of 72 cars for a normal IMSA race. Three Porsche 934s were entered and designed as the race favorites. A single Chevrolet Monza was entered for Jim Trueman-Jerry Thompson and Don Yenko. John Greenwood had brought his 1976 car and he proved fast by qualifying third overall. But the Porsche 934s seemed to be the cars to beat. The race seemed to prove this statement true and the two Porsches of Peter Gregg-Jim Busby and Danny Ongais-Ted Field clearly dominated the opening laps. The Interscope car was soon losing ground, as it suffered from two punctures which dropped the car to fiftieth position after repairs were effected. The Brumos car had built a six lap lead after eight hours of racing. However, after a routine pit stop, the car lost a wheel on track and had to come back to the pits for repairs. Damage had been made to the oil cooler and the suspension. The lead was taken by a Porche Carrera RSR driven by George Dyer and Brad Frisselle. The Brumos car began to push hard in order to take back the lead but some other minor mechanical problems finally prevented Gregg and Busby from doing so. At the end, it was George Dyer-Brad Frisselle who took the win, five laps ahead of Diego Febles-Hiram Cruz on a similar car. They managed to keep their position by a mere half lap over the Porsche 934 driven by Peter Gregg-Jim Busby, who had deserved to win, but were unlucky. The GTU class was won by the Porsche 911S driven by Rainer Brezinka-Gary Hirsch and Fritz Hochreuter. It was an entire Porsche sweep as the German make took the first 11 overall positions. This race was to be the last success for the Porsche Carrera RSR.
The next race was to be held at Road Atlanta, a 100Miler. Eight Porsche 934s were entered and would face the opposition. Al Holbert was the fastest qualifyer and easily won his heat. Carl Shafer was second and won his too. At the start of the race, Carl Shafer took the lead and seemed to pull away from Al Holbert, who knew his engine might not last. Carl Shafer had a 10s margin after 30 laps : he began to ease up his pace. Unfortunately for Carl, his transmission began to deteriorate, and he lost a couple of gears. Al Holbert would finally overtake him to take his fifth straight victory on this track. Carl Shafer finished second and George Dyer was third on a brand new Porsche 934. David Hobbs, starting from the back of the pack, took fourth in his BMW 320i Turbo. Sam Posey was the new driver for Bob Sharp Racing and he won the GTU class, finishing 12th, just ahead of Bob Bergstrom's Porsche 911S.
Next race at Laguna Seca was won by Danny Ongais who score the first ever victory for a Porsche Turbo. He had won his qualifying heat as did David Hobbs : they started on the front row. At the start, Danny Ongais was second but he passed David Hobbs in the fourth turn and was never to be caught again. David Hobbs was soon having trouble and pitted due to a problem with the injectors : he lost three laps. Behind, George Follmer and Jim Busby were fighting hard. Jim Busby finally took the advantage to take second overall. The fourth position went to Michael Keyser in his Chevrolet Monza. He won a big battle between him, Greg Pickett and Tom Frank, all three driving Monzas. 
Walt Maas returned to victory lane and won the GTU class on his Porsche 914/6, he defeated Sam Posey driving a Datsun.
At Mid America, Al Holbert won his heat and Hurley Haywood won his one. At the start, Al Holbert took the lead, while Carl Shafer, charging from the back of the pack, was second after five laps! David Hobbs had retired with engine problems and Jim Busby was out with a broken motor on his Turbo. Carl Shafer was chasing hard and was catching Al Holbert when a flat tyre forced him to pit. When he restarted, the engine did not go as well so it was over. Hurley Haywood and George Dyer fought hard for second. Hurley Haywood finally had trouble and could not use as much boost as he wanted to, so he had to settle for third. Walt Maas again won the GTU class over Bob Bergstrom.
At Lime Rock, Al Holbert won again. It was the first time Porsche did not win at Lime Rock in IMSA racing. He was simply no match for the others, and only David Hobbs could challenge him. But the little BMW had a fuel line come adrift a few laps from the finish. Hurley Haywood lost one lap at the begjnning of the race but he managed to work his way through the field to finish second. George Dyer had brought his Carrera and he took third, just ahead of Brad Frisselle, driving a Chevrolet Monza.
Walt Maas again won GTU in his Porsche 914/6 but Sam Posey was the hero of the day when a flat tyre forced him to stop : he lost two laps in the process but finally finished second, 35s behind Maas.
At Mid Ohio, David Hobbs had his efforts rewarded with a deserved victory. Al Holbert and David Hobbs shared the front row but, on the pace lap, Al Holbert realized that a rear wheel was loose. He had to stop and started from the back of the pack. Danny Ongais took the lead at the start and held it until the eleventh lap. An off course excursion damaged his suspension and David Hobbs took the lead. As Al Holbert was steadily working his way through the field to finish second, Warren  Agor and Tom Frank took third and fourth in their Monza. As per usual, it was a Sam Posey and Walt Maas battle throughout the race, with the Datsun taking the GTU victory.

Al Holbert had a fantastic race at Mid Ohio, finishing second after starting last.
Copyright Mark Windecker

Brainerd had not hosted an IMSA event for years. David Hobbs was the fastest qualifier, just ahead of Al Holbert. At the start of the race, Danny Ongais took the lead at the first turn, Al Holbert was second leading Hurley Haywood, George Dyer, Carl Shafer and David Hobbs. At it turned out, those six drivers would simply put the best show since long. The cars would stay nose to tail for ten laps. George Dyer was the first to quit when he had to pit with turbo problems. The five cars did not break until the halfway mark when a torrential rain storm swept the circuit. From that moment, it was a matter of strategy. David Hobbs was the first to pit. After everyone had stopped, Hobbs was now in the lead ahead of Danny Ongais, who was 20 seconds down. However, his car was suffering from its differential. Soon, Danny Ongais was in front, and eventually won the race. David Hobbs retired soon and Hurley Haywood took finally second, just ahead of Al Holbert. George Dyer finally took fourth. Walt Maas was sixth overall and won again the GTU category, Sam Posey finishing again second in class and eighth overall, behind John Paul, driving a new Chevrolet Monza. This race saw the debut of the new Greenwood GT car. It did not have a great race as the car seemed to be slowed by its automatic transmission. A manual gearbox would be used later.

1977 : the coming of the turbos, part 2

Round 9 took place at Daytona for the usual Paul Revere 250, a race that started at midnight. The pole had been set by John Greenwood who made an interesting comeback with his new Corvette. He was slightly under his own track record. But the race proved to be as short as one lap as the clutch failed just after the start. Brad Frisselle was out soon after John Greenwood. After a few laps, most of the competitors were out and Hurley Haywood was in the lead with a few laps remaining. He lead George Dyer when his clutch let go and had to reduce his pace to a limp. George Dyer could easily get back the lead and he finally won the race. Gary Belcher finished third, equally in a Porsche 934. Phil Currin was fourth in his familiar Corvette. Sam Posey won the GTU class over Dave White-David McClain Porsche 911S.
The next race was a first-ever as it was a GTU event in Hallett, Oklahoma. The biggest problem for the racers appeared to be the heat, which was nearly unbearable . The race was hot for the Sam Posey, Walt Maas and Dave White who put up a big show. The first one to falter was Sam Posey who suffered from heat exhaustion at the two-third mark. The race was then a hard fought battle between Walt Maas and Dave White. The latter put a wheel off the track on the 42nd lap to let Walt Maas cruise to a well deserved victory. Dave White was second and Sam Posey finished third, just ahead of Bob Bergstrom and George Drolsom, both driving a Porsche 911S.
Round 11 at Sears Point saw a separate GT and GTU event. Al Holbert was on the pole, just besides David Hobbs. At the start of the race, the little BMW jumped to the lead. Al Holbert would stay in his trail during the most part of the race. A few laps from the finish, however, he picked up some debris on the track and had to pit to change a tyre. He dropped a few positions and worked his way back to second. Third was Brad Frisselle, who wound up his best result of the year, just ahead of George Follmer, driving an outdated BMW 3.0CSL, entered by Vasek Polak.
The GTU race was a hard fought battle between Walt Maas, Sam Posey, Dennis Aase and Bob Bergstrom. The three first drivers led the race for a while, with Bob Bergstrom trailing close behind. Sam Posey and Walt Maas would have a coming together and Walt Maas had to pit to change a tyre. Dennis Aase would be happy with that and he won the race in front of Sam Posey. Walt Maas finished third and Bob Bergstrom fourth.
Next race was held at Pocono, Al Holbert's hometrack. Danny Ongais and David Hobbs started from the front row. The two cars led the earlier stages of the race, but they would not last for long. Danny Ongais blew a turbo and David Hobbs broke an axle. After that, Al Holbert motored to an unchallenged win. Hurley Haywood was second for the most part of the race, but he began to have a problem with his car. Tom Frank closed in and passed Hurley Haywood. He unfortunately spun while overtaking the Porsche. He lost his place but finally got by the Porsche a few laps later. Milt Minter finished fourth in another Porsche 934. The GTU was a usual Walt Maas and Sam Posey battle. The Porsche driver took again the class victory, finishing ninth overall.
The Mid Ohio 3Hours race was a special event, with the usual GT and GTU cars being joined by Group 5 cars. Porsche 935s would compete only for prize money, and not for the points.

The start of the Mid Ohio 3 Hours : Jim Busby is just ahead of Peter Gregg in his Porsche 935

Copyright Mark Windecker

At the end of the race, it was Peter Gregg who took the win on his Porsche 935, just ahead of Jacky Ickx-Skeeter McKitterick Vasek Polak car, Jim Busby-John O'steen were third. The next spot was taken by the Porsche 934 driven by Hurley Haywood-Bob Hagestad, who won the points for the Championship, and keeping Hurley in the battle for the Championship.

Hurley Haywood finished fourth but earned the Championship points

Copyright Mark Windecker

They were just ahead of Danny Ongais-Ted Field 934 and Charles Mendez-David Cowart Porsche Carrera. Al Holbert had engine and exhaust problems to finish 15th on the Monza he shared with John Morton. The GTU class was won by Walt Maas who had an easy victory after Sam Posey blew his engine. Second went to the Porsche 911S driven by Chris Gleason and Mike Yoder finishing four laps down Maas' Porsche 914/6.

Sam Posey did not finish that race

Copyright Mark Windecker

The Road Atlanta fall event was a premiere as Al Holbert lost the race to David Hobbs BMW. The Englishman had won the pole but had a disastrous start, and found himself in seventh position. Al Holbert took the lead for nine laps, followed by Hurley Haywood, who inherited the lead for two laps. But David Hobbs had stormed through the field to take the lead on the eleventh lap, and was never relinquished. He built a solid margin over Al Holbert, who took second, and Hurley Haywood. Danny Ongais was fourth, followed by John Paul's Chevrolet Monza and Carl Shafer on his usual Camaro, who had to slow down after two off-course runs damaging his car.
The GTU race was a bit different with Dennis Aase winning the pole. The race was a tight battle with four cars nose to tail. Dave White, in the course of the action, hit Walt Maas rear end, which caused the Porsche 914/6 to slow down. Sam Posey and Dennis Aase could have a race of their own, battling all the way to the finish. On the last lap, they were still stuck together, and the Porsche driver won by a 0.015s margin.
The next race was to be held at Laguna Seca for the second time of the year. There, it was all David Hobbs, who had won the pole. At the start, he jumped in the lead, closely followed by Al Holbert, who did not want to lose any ground. They would put another good two-car show. Al Holbert was in the lead for the last third of the race, with David Hobbs trying several passes on different places of the track. He finally made it on the outside of turn eight. David Hobbs won the race, but Al Holbert clinched the title on this very race, as Hurley Haywood had a dnf. He had a shunt with another car that damaged his suspension and finally, he had to retire. Brad Frisselle finally took third in his Chevrolet Monza, followed by Roy Woods and Tuck Thomas, both driving Monzas. George Dyer was sixth. The GTU  race within the race saw another Walt and Sam show, but they were joined by Dennis Aase. Starting down on the grid due to a bad heat race, Sam Posey had to fight his way back. But he could not catch the duo Aase-Maas who was having a great show. Walt Maas finally used the traffic to  take a definitive advantage over Dennis Aase. Sam Posey was third, and Walt Maas had clinched th GTU Championship.

Walt Maas won the 1977 GTU Championship driving this Porsche 914/6

Copyright Mark Windecker

The season finale was held at Daytona. There, Al Holbert was facing the best field of the year. A lot of Porsche 934s were entered as well as new cars, such as the Group 44 Jaguar XJS driven by Bob Tullius, Charlie Kemp Ford Cobra II, and the BMW 3.0CSL driven by Kenper Miller. Only three Chevrolet Monzas were entered for Al Holbert,  John Paul and Hoyt Overbagh. The race did promise a lot, but in fact, it was over well before the end. David Hobbs and Danny Ongais had jumped to an early lead, as Jim Busby blew his turbo on the first lap. Two laps later, Danny Ongais spun and damaged his car suspension. David Hobbs was hit by another car and retired with a broken water line. The circuit would soon become some kind of car cemetary, with bits of bodywork strewn everywhere. A lot of cars were then forced to stop with cut tyres, including Al Holbert. When it happened to be unlikely to be safe for the racers, the officials had no other solution than to red-flag the race. At the restart, a lot of contenders were out and Hurley Haywood was able to take the lead and managed to keep this position until the finish. George Dyer was second for the most part of the race, but he had to retire after an electrical problem did stop the car definitively. The biggest surprise of the race was Kenper Miller's second place, which was the car's best result of the year, third was Cliff Kearns Porsche 934, which he shared with Milt Minter. After an early pit stop due to a puncture, they lost two laps but made their way back to third. Fourth place went to Lamar Mann and Guido Levetto on a Corvette. The GTU class was won by Rusty Bond-Ren Tilton on a Porsche 911S who won over Chiqui Soldevilla on a similar car. None of the points contenders were entered for that final race.
Al Holbert had finally won the IMSA Championship for the second time in a row. However, he would not attend the 1978 Championship and the Porsche 935 was now eligible for points in the IMSA Camel GT Challenge. It would be the last time an American car would win overall.

Porsche Carrera RSR : the car that made IMSA, part 1

The Porsche Carrera RS has been introduced in the US road racing scene in 1973. From that moment, it has become one of the most successful car ever. The first race of such a car was to happen at Daytona in 1973. This race was the first of the World Sportscar Championship and, there it faced true racing Prototypes as Matra, Mirage and Lola. Not still homologated in GT, the cars were forced to run against stronger machinery. Two brand new Carreras were entered by Brumos Racing and Penske Racing. These were RS cars because fitted with 2,7L engines.The drivers were Peter Gregg and Hurley Haywood on the Brumos car and Mark Donohue and George Follmer on the Penske car. After eight hours of grueling fight between the two sister cars and the retirement of every works car, the Brumos car took the lead of the race! Now the two cars were fighting for overall victory. The Brumos car eventually won the race and had set the Carrera's future in a significative way. From that moment, the Carrera began to dominate the series when introduced in IMSA racing. The first other team to acquire a Porsche Carrera RSR was Dave Helmick's and Gray Egerton's. The first car won at Sebring that year with Peter Gregg, Hurley Haywood and Dave Helmick at the wheel. The Porsche Carrera had won two of the greatest international races in its race debut. Fitted with a 2,8L F6 engine given for 300hp, the car was one of the most effective ones when in the hands of potent drivers. Its low fuel consumption coupled with a great reliability made this car a winner. The 1973 Porsche Carrera was the IMSA Champion with Peter Gregg that year.

Michael Keyser finished second and was the most serious contender to Peter Gregg.
Copyright Mark Windecker

1973 Standings

1	Peter Gregg	Porsche Carrera RSR
2	Michael Keyser	Porsche Carrera RSR
3	Hurley Haywood	Porsche Carrera RSR
4	Maurice Carter	Chevrolet Camaro
5	Gene Felton	Chevrolet Camaro

In 1974, a new version was born, this time the engine grew up to 3,0L. With a new tail section and an increase of power, such a car was nearly unbeatable. Furthermore, their number increased in a significant way. The IROC Series was no stranger to this fact. At the end of the 1973 season, a string of a dozen cars was left unused. These cars needed very few changes to adapt to the IMSA rules, and they found new owners very quickly. The 1974 season began with the cancellation of two of the longest events in the schedule. The Arab-Israeli war had put an embargo on the fuel and restrictions were made to long distance races. The season began thus at Road Atlanta with a 6Hour event. This first race was won by Al Holbert and Elliot Forbes Robinson.

Al Holbert finished fourth in the 1974 Championship

Copyright Mark Windecker

1974 Standings

1	Peter Gregg	Porsche Carrera RSR
2	Milt Minter	Porsche Carrera RSR(Chevrolet Corvette)
3	Michael Keyser	Porsche Carrera RSR
4	Al Holbert	Porsche Carrera RSR
5	Steve Behr	Porsche Carrera RSR(BMW 3.0 CSL)

In fact, the Porsche Carreras won all but one event this year, clearly dominating the series. Peter Gregg emerged again as the series champion, as he proved his talent once again. This domination proved to become some kind of a threat to the series, as John Bishop sensed the fact that it would bore the crowds. The solution would be to bring new competitors to the German Make. It would take some time before the opposition would clearly materialize.

For 1975, the Porsche fleet would face new challengers as BMW brought a pair of factory CSLs, and the new AAGT category was now launched. These welcome additions would add some excitement to the series and the attendance increased in a significant way. A new step was now accomplished to International recognition. The first race of the season was the 24 Hours of Daytona which saw a new Porsche Carrera sweep. Once again Peter Gregg and Hurley Haywood won that race. At Sebring, BMW proved to be the true Porsche contender and won the race with Hans Stuck-Allan Moffat-Sam Posey and Brian Redman driving. A quite international entry! The remainder of the season was a hard fought Championship between Porsche and BMW. John Greenwood won the only non-German race at Daytona in November for the Finale.

1975 Standings

1	Peter Gregg	Porsche Carrera RSR
2	Hurley Haywood	Porsche Carrera RSR
3	Al Holbert	Porsche Carrera RSR
4	Hans Stuck	BMW 3.0 CSL
5	John O'steen	Porsche Carrera RSR

The 1976 season would be the first season a Porsche Carrera did not win the Championship. The AAGT class was now fully operational and top-level contenders such as Al Holbert and Michael Keyser had made the move and purchased Chevrolet Monzas. Even Peter Gregg did not drive a Carrera that year, he had arranged a deal with BMW to run a CSL. However, the Porsche Carrera proved to be a solid contender in long distance races. Al Holbert and Michael Keyser won at Sebring. Jim Busby won at Ontario, George Dyer at Lime Rock, Jim Busby again at Sears Point, Mid Ohio and Laguna Seca 2. It would the last year the Porsche Carrera would win as much races. Clearly, the cars suffered from a lack of power. Porsche had already built a new car that would replace the Carrera, but John Bishop banished the 934 for the 1976 season. Porsche's Joe Hoppen found a new home for these cars in the SCCA Trans Am. This series needed a strong push to get revived, and Porsche did a lot while bringing these cars to the newly reborn series. Seeing this fact, John Bishop finally admitted that he made a mistake, and the Porsche Carrera had its successor. The 934 made its racing IMSA debut at Mid Ohio at the end of the 1976 season. The Porsche Carrera was not finished and soon would be raced for years in the new GTO and GTU categories.

1976 Standings

                                                           

1	Al Holbert	Chevrolet Monza(Porsche Carrera RSR)
2	Peter Gregg	BMW 3.0 CSL
3	Jim Busby	Porsche Carrera RSR
4	Michael Keyser	Chevrolet Monza(Porsche Carrera RSR)
5	George Dyer	Porsche Carrera RSR

Porsche Carrera RSR : the car that made IMSA, part 2

The Porsche Carrera was not over in 1977 as it began successfully the 1977 season by winning the 24 Hours of Daytona. Driven by John Graves-Dave Helmick and Hurley Haywood, the car defeated the Porsche 935 turbos to win one of its last great international success. The 12  Hours of Sebring was the very last with George Dyer and Brad Frisselle at fhe wheel. The two drivers  finished five laps ahead of Diego Febles and Hiram Cruz in a similar car. The Porsche Carrera would prove its lack of hp in the shorter events. At Road Atlanta, John Paul was the best finisher in his lightened car, which sported a high wing, but he could do no better than seventh.

John Paul drove his lightweight Porsche Carrera at Mid Ohio in 1977

Copyright Mark Windecker

Even when highly modified, it seemed that, in 1977, the cars would be simply outpowered. You must not forget that it was a three year car. Even such a successful car could not win forever. George Dyer almost made a miracle at Mid America when finishing second in a lightweight car. At Lime Rock, he finished third overall and fifth at Mid Ohio. Then he switched to a more powerful 934 with which he won at Daytona the Paul Revere night run event. Then, the different cars driven by Tom Frank or Robert Frostrom wound up one sixth and one seventh at Sears Point and Pocono. David Cowart and Kenper Miller were sixth at the Mid Ohio 3 Hours but David Cowart could do no better than eleventh at the Road Atlanta fall event. Laguna Seca saw one anonymous result by Eberhard Braun in fifteenth position and Mauricio de Narvaez made a promising debut at the Daytona Finale and placed fifth.

For 1978, IMSA introduced a new set of rules as the GTX, GTO, AAGT and GTU classes were now the classes to be available for the fans. A new area for success was by this mean created for the Porsche Carreras which could fight against similar GT cars, mainly Camaros, BMW CSLs, Mustangs or others. The 1978 season would begin successfully with a third place overall for the Diego Febles and Hiram Cruz car, and a GTO class win. At Sebring, it was John Paul and Bonky Fernandez who who had a fifth overall for another class win. At Talladega, Bonky Fernandez and Dave Cowart took a fourth behind three Porsche 935s. Road Atlanta was a bit different as Kenper Miller brought an ex-Peter  Gregg BMW 3.0CSL in ninth overall and beat Dave Cowart's Carrera. At Laguna Seca, John Morton's similar CSL defeated Howard Meister Carrera to win the GTO class. At Hallett, Kenper Miller had a new win over Howard Meister and Werner Frank Carreras. Lime Rock would see another another Porsche defeat but it was Diego Febles Ford Capri who took the class laurels, this time over Dave Cowart and Howard Meister. At Brainerd, Dave Cowart had its first victory of the year : he defeated Paul Brand in a Camaro. Daytona saw a new victory by Kenper Miller's fast BMW as he won over Mauricio de Narvaez car, this one being followed by Diego Febles and Bonky Fernandez cars. Howard Meister went for the first time into Victory circle at Sears Point. There he won over Bob Harmon and Kenper Miller's BMW who could do no better than third. At Portland, Dave Cowart won over Bob Bergstrom and Ren Tilton, who drove a 2,7L Porsche 911. Mid Ohio was a  victory for Dave Cowart-Mauricio de Narvaez, just ahead of Bonky Fernandez-Walt Bohren and Diego Febles car. At Road Atlanta, Howard Meister had a very good run to win the GTO class : he beat Kenper Miller's BMW on a track where horsepower was on the BMW's edge. The Daytona Finale was the worst results for the Porsche horde as Rick Thompkins took the win in his Corvette, second was Bob Tullius on his Jaguar XJS, Mauricio de Narvaez finished third, Diego Febles and Bob Beasley took the two next spots. At the end, Porsche won the GTO title with its Carrera.

Dave Cowart won the GTO title in 1978

Copyright Mark Windecker

Dave Cowart won the first GTO title aboard a Porsche Carrera, second was Diego Febles, who shared his drives between a Porsche Carrera and a Ford Capri. The Porsche Carrera's career had taken a new start, and victories for these cars were far from being over. The 1979 season would prove even more successful for these cars as Howard Meister
brought a very well prepared car to seven wins and an easy final GTO Championship. The season started at Daytona and the Porsche Carreras were beaten for the first time by a very reliable Ferrari 365GTB4 driven by John Morton and Tony Adamowicz. They took a fantastic second overall behind a single Porsche 935, driven by Ted Field-Danny Ongais and Hurley Haywood. The first Porsche Carrera finished at a distant eighth place overall, far away from the leading Ferrari. It was even behind the best GTU cars, which looked quite unbelievable! Things changed at Sebring as Bonky Fernandez-Tato Ferrer and Chiqui Soldevilla took a well deserved victory, three laps ahead of Horst Kroll-Rudy Bartling car, and four over Tony Garcia-Juan Montalvo and Alberto Vadia on another Carrera. Howard Meister entered his first race at Road Atlanta, and he easily won the GTO category over Mauricio de Narvaez on a Carrera too, and Carl Shafer's Oftedahl Camaro. At Riverside, Dave Cowart was co-driven by Kenper Miller, who had not brought his BMW, to win the class over Tony Garcia and Terry Herman, the pair finishing on the same lap as the winners. Howard Meister had a successful run at Laguna Seca and he won over Honorato Espinosa, Tato Ferrer, Mauricio de Narvaez, Dave Cowart, Terry Herman, Tony Garcia. In fact, Porsche took the first eight GTO spots in this race! At Hallett, Porsche dominated the same way and Howard Meister again won the race over Dave Cowart and Honorato Espinosa. At Lime Rock, it seemed that Howard Meister got accustomed to victory and he won over Dave Cowart and Mauricio de Narvaez. At Brainerd, however, he had to fight hard against Tony de Lorenzo, but he won again over the Corvette. Third was Phil Currin in his usual Corvette. At the Paul Revere race, Phil Currin did bring his car to victory and he beat the Porsches on the Daytona track. Jorge Cortes and Howard Meister took second and third. Howard Meister was partnered by Alan Johnson to win the category at Mid Ohio over Luis Mendez Porsche and Mauricio de Narvaez-Tony Garcia for a new 1-2-3 for Porsche.

Tony Garcia and Terry Herman drove this Porsche in 1979

Copyright Mark Windecker

At Sears Point, Howard Meister was the winner again and Luis Mendez was second, Mauricio de Narvaez and Dave Cowart were next. Portland was quite different as Neil Shelton took a surprise victory in his Carrera over Phil Currin in his Corvette, and Howard Meister in his Porsche. The Road America 500 Miles were a new defeat for the Porsches, and it was a unique victory for the Group 44 Triumph TR8, driven by Bob Tullius and Bill Adam who won over the Tony Garcia-Terry Herman car, third was the Mauricio de Narvaez-Albert Naon car. The fall Road Atlanta event was another non-Porsche victory, as Kenper Miller took his sole 1979 victory over Bob Tullius Triumph and Tony de Lorenzo Corvette. The best Porsche was Francisco Romero's fourth place. Surely one of the worst race for the Porsche contingent. The Daytona Finale would look as a revenge for the German make : Mauricio de Narvaez won over Carl Shafer's Camaro. Werner Frank took third in his Porsche 934. At the end, Porsche had proved its consistency, and won a new GTO Championship.

The 1980 would be as successful for the Carrera and a new driver would emerge from the GTO ranks : Luis Mendez. The season began as per usual at Daytona with a victory for the Tony Garcia-Alberto Vadia and Terry Herman car, second was the Mauricio de Narvaez-Albert Naon and Ricardo Londono car. At Sebring, the Porsche squadron had to face a new threat as the Group 44 Triumph TR8 was entered for Bob Tullius and Bill Adam. This threat did materialize in a very clear victory for the Triumph drivers. They won by a fourteen laps margin over the best Carrera, the Luis Mendez-Jaime Rodriguez and Ernesto Soto car. The Werner Frank-James Brolin Porsche 934 was third. Road Atlanta was a new non-Porsche victory : Phil Currin won over Bob Raub Camaro and Luis Mendez, the best Carrera driver. The Riverside race proved to be a true enduro as the Porsche Carrera driven by Tony Garcia-Terry Herman survived the 5Hour race to take the class win over Ernesto Soto and Pierre Honegger car. The next race was  to be held at Laguna Seca. There the Tony Garcia car defeated the Triumph in a convincing manner. Third was Luis Mendez, just behind Bob Tullius. At Lime Rock, Luis Mendez earned his first victory of the season. He won over a pair of Triumph TR8s, driven by Bob Tullius and Bill Adam, and John Caruso, on a Corvette. Brainerd was a special event, featuring a GTO-GTU race. Luis Mendez won overall, just ahead of two Mazda RX7s, driven by Jeff Kline and Brad Frisselle. Tony Garcia was fourth, and second in GTO. The Porsche Carreras were unchallenged on that race. At Daytona, it was another story and the Triumphs driven by Bob Tullius and Bill Adam won the class over Ernesto Soto, the best Porsche driver. At Sears Point, it was again Luis Mendez, who won over Casey Mollett's Datsun 280Z and Tom Marx on a Carrera too. He continued his winning streak by winning at Portland over Phil Currin Corvette, and Tony Garcia Carrera. At Mosport, once again the Triumph TR8 proved the best and outlasted the Porsche Carreras. Mauricio de Narvaez-Tony Garcia were second, eight laps down. The next race, at Road America, was again won by the Triumph, who won the class over the Porsche 911, fitted with a bigger engine, driven by Dennis Aase and Bob Bergstrom. Tony Garcia and Terry Herman were third. At Road Atlanta, again Porsche was beaten, this time by Phil Currin in his Corvette. Bob Tullius Triumph was second and Dennis Aase Porsche Carrera was third. The final race at Daytona proved again difficult to the Porsches as the two Triumphs made it one-two. Bill Adam won over Bob Tullius and Carl Shafer in his Camaro. The best Porsche was the Roger Schramm-Werner Frank car, which placed fourth. At the end of the season, it was a Porsche driver who won the title, but it looked far more difficult to the Porsche. The next year would be even be worse : new cars, such as the BMW M1, would be far more powerful. The car was getting old and was no longer developed. The next chapter will be dedicated to this career end.

Porsche Carrera RSR : the car that made IMSA, part 3

In 1981, the Porsche Carrera RSR was continuing to be one of the most popular cars. Even though it became to be really outdated, many teams and drivers were counting on its reliability. At Daytona however, it was a 2,5L Porsche 911 that proved to be extraordinary reliable by finishing third overall behind two Porsche 935 Turbos. At Sebring, it was still a Porsche Carrera, driven by Chuck Kendall-Pete Smith and Dennis Aase that took fifth overall to win the GTO category. It was a neat victory by a well driven car. For the sprint races that were to be held after, the cars were simply outclassed by the newer and much more powerful cars. At Road Atlanta, Dave Cowart took an easy win and the best Carrera could do no better than fifth. At Riverside, the car driven by John Hotschkis-Robert Kirby was again fifth in class. Terry Herman was third at Laguna Seca in a standard car. At Lime Rock, Tico Almeida-René Rodriguez took a fifth in their well prepared car. At Mid Ohio, Tim Selby and Earl Roe took fourth in their car but they were behind eight GTU cars! It seemed that the cars could no longer fight for the top spots. At Brainerd, no Carrera were to be entered, it was the first time in IMSA history that, since its introduction in 1973, no Carrera took part of an IMSA race! It seemed that the ring of changes was on its way. After that every Carrera entrant would post some anonymous result. At the Paul Revere race, Doug Lutz finished 29th overall, and tenth in class. But the winning BMW had finished an astounding second overall! The gap between the best GTO cars and the Carreras seemed to increase at a very high rate. At Sears Point, René Rodriguez put an excellent fourth in class, on a slow circuit, needless to say. At Portland, Neil Shelton was a fantastic second to David Cowart : he managed to finish ahead of Don Devendorf's powerful Datsun 280ZX Turbo! Some kind of a feat! At Mosport, the local Carrera driven by Fritz Hochreuter-Rudy Bartling and Norm Ridgely took an honest sixth in class, but finished behind the top GTU runners. At Road America, the Earl Roe-Tim Selby entry was again the best Carrera, and finished second in the GTO category. Once again, the best GTU contenders were ahead! At Mid Ohio, the Bob Beasley-George Stone car finished fourth. At that time, the newly introduced Porsche 924GTRs began to wind up better results. These cars were powered by turbocharged engines and proved to be honest racers. The Road Atlanta fall event was as disappointing for the Carreras as René Rodriguez and Ernesto Soto finished sixth in the GTO category. At Pocono, the Steve Southard-Mark Altman-Gary Altman car was forth in the GTO class. Three BMW M1s took the three first GTO spots. For the Daytona Finale, the best car was sixth : it was Roger Schramm-Werner Frank who placed sixth behind more powerful cars.
The 1982 began with the usual 24 Hours of Daytona. Here, the Tico Almeida-René Rodriguez and Ernesto Soto Carrera finished a fantastic fifth overall, and second in GTO, behind a factory Mazda RX7. It proved once again its extraordinary reliability in long distance races. The Porsche Carrera was not quite over and would be seen for some more years. At Sebring, Diego Febles-Tato Ferrer-Chiqui Soldevilla did ever better than at Daytona by finishing fourth overall and first in GTO. It was a different story at Road Atlanta where the best car, the Tico Almeida one, could do no better than ninth. Once again, the speed matter problem! At Riverside, the Tico Almeida-René Rodriguez car was again the most efficient one and finished tenth overall : they won their class but finished behind the best GTU cars. Again at Laguna Seca, the best entry could do no befter than fourteenth, and seventh in GTO. At Charlotte, the Ken Madren-Denny Wilson pair finished fourth in GTO. At Mid Ohio, Tim Selby again proved that his car was outclassed and finished a distant eighth.

Tim Selby finished eighth at Mid Ohio in 1982

Copyright Mark Windecker

At Lime Rock, the sole car, driven by Earl Roe, was an early dnf to finish last in class! Ken Madren had a better race at the Paul Revere and finished sixth, which was quite a good result. No Carrera was entered at Brainerd and Al Thomas was the best entry at Sears Point, finishing a distant eighth in class. Karl Durkheimer was the best finisher at Portland with a fifth but the next race at Mosport would be again the Tico Almeida-René Rodriguez car who finished second to the Electrodyne Porsche 934. It was a 6Hour event, the typical long distance suited to the undauntable Carrera. The third place was again taken by a Carrera driven by Roger Schramm-Rainer Brezinka and Fritz Hochreuter. At Road America, the T and R Carrera was the best placing car. The Madren-Wilson pair took a fourth at Mid Ohio and the Lance van Every-Ash Tisdelle entry took a third at Road Atlanta. With a seventh at Pocono, things did not improve as for the Daytona Finale, where Lance van Every-Ash Tisdelle took a seventh in GTO, and fifteenth overall.
For 1983, you could still find your usual Porsche Carrera, and even as high finishing as fifth overall for the Diego Febles-Kikos Fonseca-Roy Valverde, however, they were beaten by the fantastic Mazda RX7 entered by Racing Beat. It was a fantastic result for such an old car. The Miami event, which was a separate GTO race, saw a fourth place by Jamsal, some kind of interesting result that those cars could produce on street circuits. Sebring was a strange race as it was won by a GTO car, but it was the Garretson Porsche 934 that made it. This car was much more powerful than the Carreras but the Luis Gordillo-Manuel Villa and Chiqui Soldevilla finished seventh overall and third in GTO. For the next event, Kikos Fonseca did his best to finish fifth in class. At Riverside, the Rick Borlase-Michael Hammond car was fifth in class, far away from the GTO winning Porsche 934. It was a disaster at Laguna Seca as no Carrera made it to the finish. At Charlotte, Jack Lewis-John Ashford were eighth, out of the winning pace. The only car entered at Lime Rock was a dnf as well. Things remained unchanged at Mid Ohio with a fifth in class for Al Leon-Wayne Pickering, in a rainy event. The same car was driven by Jack Griffin-Paul Gilgan at the Paul Revere for a eighth in class result. Brainerd seemed to be the race to avoid as no Carrera was entered. Terry Herman again was fifth, very far from the Electramotive winning Datsun 280ZX. Unknown drivers Parke Duff-John Gilson were the best Carrera finishers at Portland, with a fourth in class. At Mosport, the best car was the Bobby Hefner-Jack Griffin-Wayne Baker car who finished fourteenth overall and fourth in class. Philip Byrd and Richard Silver took their beautiful car to a sixth in class at Road America. Pocono was to give a sixth in class to John Hulen-Ron Coupland and the Daytona Finale was a fifth for the Jack Griffin-Chris Price entry.
In 1984, the Porsche Carrera was no longer a winning car. But it was a car that would be seen for some more yezrs on the track. It had been adopted by so many drivers that it was some kind of an unbypassable car. The Daytona race was not so bad for the Carrera squad as the Lance van Every-Ash Tisdelle was second in class, but the winning Camaro was nine laps ahead. At Miami, Luis Mendez proved he had not lost his racing abilities and finished third behind two GM products. That same Luis Mendez finished first in class at Sebring, but far behind the GTU winners. But did it matter? For the purists, surely it did. Bob Beasley and Jack Lewis were fourth at Road Atlanta, Larry Chmura-Brent Regan and Jon Koobation were second to Roger Mandeville Mazda RX7 at Riverside and Gary Auberlen was the only entrant, and a dnf, at Laguna Seca. At Charlotte, Lance van Every had a good race and finished fourth on a horsepower track. Lime Rock saw no Carrera and Mid Ohio was a fourth in class for John Hulen-Ron Coupland. It was becoming clear that the Porsche Carrera would never win any more race, even in its category. George Hulse would end up fourth at Watkins Glen. At Portland, Gary Auberlen and Peter Jauker finished fourth, Bob Zulkowski was very far away at Sears Point and John Hulen-Ron Coupland finished eighth in GTO at Road America.

John Hulen-Ron Coupland at Road America in 1985

Copyright Mark Windecker

Gone were the days where you could count on a Porsche Carrera to win its class! By now, no more than two or three cars could be seen on the track. And it was only for fun. From that moment, Porsche Carreras became difficult to be seen. The Luis Mendez car would finish seventh at the Daytona Finale. The rules changes would soon raise the displacement to 2,8L and then 3,0L. The ubiquitous Porsche Carrera/Porsche 911 would soon evolve in the lower class. The glory days of the Carrera were definitively over, its career would have lasted as much as 15 years. Many success were met by a lot of drivers and this car remains one of the most successful in IMSA history. The Porsche Carrera has really made IMSA.

 

The categories : what are they?

John Bishop had helped draw FIA rules for the World Championship of Makes. The FIA Appendix J group 2 and 4 cars had only the few races to run in the US. He wanted a series based upon familiar looking cars and he thought that a Championship was needed to allow these cars to run on a regular basis. He wanted to go his own way, so he created the IMSA Camel GT Championship that would involve these types of cars :

• GTO based on FIA Group 4 cars, over 2,0Liters displacement

• GTU based on FIA Group 4 cars, under 2,0Liters displacement

• TO based on FIA Group 2 cars, over 2,0Liters displacement

• TU based on FIA Group 2 cars, under 2,0Liters displacement

All four categories were based on the FIA Rules set by Paris international homebased organisation. The main differences between the European rules and the IMSA rules were a greater liberty for tire width and cars could have less weight. Cars could also be stripped of every useless device.
These categories did evolve with time and the IMSA customized its rule book to suit to its needs. John Bishop's openminded spirit was always all ears to his racers, he wanted to equalize everyone's chance to win.
These categories were to be run until 1973, then the TO and TU were dropped, and all the cars were regrouped into the GTO and GTU categories.

GTO : Al Holbert Porsche Carrera RSR at Mid Ohio in 1974

Copyright Mark Windecker

GTU : John Hotschkis Porsche 914/6 at Mid Ohio in 1977

Copyright Mark Windecker

TU : Ray Walle Mazda RX2 at Mid Ohio in 1973.
Copyright Mark Windecker

TO : Horst Kwech Ford Capri at the same race.
Copyright Mark Windecker

In 1975, Porsche was the ever winning car, John Bishop devised a new category, aimed at breaking this domination, the AAGT was created.

AAGT : James Moyer at Mid Ohio in 1977.

Copyright Mark Windecker

AAGT standed for All American GT. These cars were to be American built ones, with a set of ultra liberal rules. Bigger engines, wider tires, less weight : all of this set was made to break the European domination in GT racing. The Chevrolet Monza was the best example of what could be done with two titles in 1976 and 1977 for Al Holbert.
In 1976, Porsche introduced its 934 Turbo, a true racing car with tremendous horsepower. John Bishop did not allow this car in his series as he thought that racing costs would rise. In fact, Porsche did have a year of waiting and, in 1977, the 934s were showing the way to the future. Cars would be allowed to run with wider tires and big wings. But they did not dominate the series and the races were always spectacular.

For 1978, things went the turbo way, as the Porsche 935 was the car to own, and the rules did change a lot.
GT designed  cars that conformed to FIA  Group 4 rules. They all run on smaller wheels. in 1979, Porsche 934 Turbos were allowed to run in this class.
GTX : similar to Group 5 cars. Lightweight bodywork, no restriction on fender shapes, chassis reinforcement and big wings were allowed. Engine modifications were permitted as long as the original block was retained. Turbocharging was the way to go. Wheel widths were restricted to 16 inches. It was a cousin from the FIA Group 5 and Porsche 935 were the cars to beat, BMW 320 Turbos sometimes proved very fast, if not reliable. They did remain production based cars, but only had their appearance, as they were true racing cars.

GTX : Bill Whittington on his Porsche 935 at Mid Ohio 1979.

Copyright Mark Windecker

AAGT : cars were no longer limited to 350ci, they could go to 454ci and use aluminium blocks as well. Even turbocharging was permitted in AAGT. 6liter cars could use 20inch wheels and larger engines could use any width.
GTU rules did not change, it was more a displacement change with the 2,0Liter limit moving up to 2,5L, then 2,8L and finally 3,0L in 1985.
American Challenge cars were allowed to run with the big cars, mainly in 1978, but then they would run their own races and have their own championship. They allowed intermediate American Sedans, with a light range of modifications permitted.

American Challenge : Gene Felton Buick Skylark at Road Atlanta in 1978.

Photo courtesy Gene Felton

In 1981, the IMSA went quite another way, and introduced a brand new category, the GTP.

Ted Field Lola T600 Chevrolet at Mid Ohio 1982

Copyright Mark Windecker

• GTP: a non production based category intended to break the Porsche 935 Turbos domination.

A wide variety of engines would be available with different flavors, and chassis were quite liberal. John Bishop did finally create his own rules system with a weight to displacement grid. Starting from a 350ci Chevy, he devised a system that could fair to everybody. The bigger the engine was, the more weight it would carry. He proved quite good as this set of rules did match everyone's will.
The first true GTP was Brian Redman's Lola T600 which crushed the opposition in 1981. In 1982, some teams switched to GTPs and the GTX cars were allowed to be further developed. Tube framed GTX cars appeared and it was John Paul Jr who won the Championship on a set of Porsche 935s and a ... Lola T600. From that moment, the GTPs would be the cars that would rule the Championship.
In 1984, Porsche introduced its famous Porsche 962, a car that would dominate the series until 1988, with Al Holbert winning the title in 1985 thru 1987. Holbert Racing was nearly a factory team as they were very well supported and quite professional. Al Holbert would soon become the President, for a short while, of Porsche Motorsport North America.

A new era was to begin, that era was to last until 1993 and made IMSA one of the most prestigious road racing series in the World. In 1985, in order to allow small displacement GTP cars to enter in a more competitive way, the Camel Lights category was created and found a relative success for small teams willing to run GTP cars with smaller engines. These cars were to be powered by non turbo engines, and their displacement could not be in excess of 3,0Liter with a weight of 700 kilos.

These are the different IMSA rules as of 1985.

• GTP
• GTX
• GTL
• GTO
• GTU

Fuel tank capacity : GTU : 110Liters Every other classes : 120Liters

Maximum displacement in Cu Centimeters

 

Minimum weight in KG

Engine eligibility

• Type 1 : Volume-produced 2-valve conventional engines and rotary engines
• Type 2 : Racing engines and volume-produced 4-valve conventional engines
• Type 3 : Surpercharged Type 1 engines(restricted to single turbo and single ignition)
• Type 4 : Supercharged Type 2 engines

Camel Light : David Loring Denali Mazda at Columbus 1987

Copyright Mark Windecker

After the Porsche era, it was the Nissan and Toyota domination. Those were factory efforts and racing costs rose up. Jaguar and Chevrolet tried to get their share but with no success. All Those cars were to be seen until 1993. Fields were getting thin and something had to be done.
After twenty years of involvement in IMSA racing, John Bishop felt it was time to take a little rest. He would finally sell his IMSA series to businessmen and the spirit would be definitively gone. The original moto "Racing with a difference" was gone.
A new concept was to be introduced : the World Sports Cars did appear in IMSA. They were the future of IMSA.