I get asked often: “What was the first IMSA GTP car?” While most people think it was the BMW M1/C that showed up at Riverside in 1981, the truth is a bit more complicated. Yes, the BMW-March was the first prototype purpose-built to the new IMSA GTP rules published in 1980, but it was not the very first race car to run in the GTP class at a Camel GT event. But before we get to that story, first some background.
The BMW M1/C debuted at Riverside in April 1981 with David Hobbs driving. The March chassis featured a modern aluminum monocoque that was mated to a normally aspirated 3.5-liter BMW engine. The team would upgrade to a 2.0-liter turbocharged motor later in the year. Photo: Don Hodgdon
The Porsche 935 was dominating the 1979 IMSA season. Although the racing was close, IMSA president John Bishop worried that no one would continue to pay to see a Porsche parade. The All-American GT (AAGT) concept had diversified the fields for a while, but the cars were increasingly uncompetitive against the onslaught of 935s, even with more relaxed GTX rules that allowed for tube frames, wider wheels and essentially unlimited bodywork. BMW, Nissan, and Ford had all been represented in the GTX class during this time, but only as solo or two-car efforts; there were no customer cars. And the price of a new Porsche 935 was in excess of $200,000, a huge sum at the time. Privateers were getting priced out of the game.
One of two Inaltera “Le Mans GTP” class cars during the 24 Hours of Daytona in 1977. The privately designed and built machines became the inspiration for the IMSA GTP class rules developed in 1980. Photo: autosportsltd.com
“We were initially inspired by the Inaltera cars that showed up for the 1977 24 Hours of Daytona in a special LeMans GTP prototype class,” Bishop continued. “The cars were fast, good looking, and competitive. Best of all, they were built with off-the-shelf parts by Jean Rondeau, a private entrant in his garage, so we knew it could be done on a reasonable budget. Given the availability of a wide variety of reliable engines, our vision was to repeat a bit of the same formula that had made the AAGT class such a success. Our goal was to create a prototype class that could compete head-to-head with the 935s but at a lower price point.”
Unlike FIA Group C, which focused on a fuel consumption formula in its rules, IMSA GTP used a sliding scale of weight versus displacement to accept as many engines as possible and give entrants freedom to decide what chassis/power package would be most competitive. The initial GTP rules set a sliding scale for cars weighing 700kg, 800kg, and 900kg using corresponding production-based, stock block engines rated at 400bhp, 500bhp, or 600bhp. This provided a place for just about everything from 335bhp Mazda rotaries to 650bhp Detroit V8s to compete on a level playing field.
The technical rules for the IMSA GTP class were kept simple in an effort to attract as many different chassis and engine manufacturers as possible. John Bishop’s hand-drawn diagram of GTP dimensions became a fixture in the IMSA rule book. Source: IMSA
“Roger Bailey deserves much of the credit for the GTP rules,” remembered Bishop. “We developed a formula where basic pushrod engines would be our yardstick. Any sophistication in the engines would then create a handicap as they got bigger, so we added weight to keep things even. If an engine had four valves per cylinder, then it had to weigh something like 1.3 times the version with two valves. We took a lot of time and care to conscientiously come up with the fairest possible set of rules that also included turbocharged engines.”
With the new IMSA GTP rule book in place by early 1980, various efforts were started at Lola Cars, BMW-March and other manufacturers to design cars. But others were at work as well.
The very first car to run in the GTP class at an IMSA race was Jim Busby’s highly modified BMW M-1 at the 1980 Road Atlanta Camel GT race in April. As Busby tells it: “The March-BMW M-1 we raced at Daytona and Sebring that year was a disaster against the 935s. We were down on power and stuck with an unreliable package. So, we stuffed a Traco Engineering Chevrolet V8 in the thing and called it a March M-1 Chevy. We couldn’t run it as a BMW or an M-1 anymore; it certainly wasn’t homologated. We asked John Bishop about it ahead of time to make sure IMSA would let us run, and he winked and said it was fine. The car had a solid monocoque, two seats, and a large, American-made V8, so IMSA let us run it as a GTP car.”
The first car ever to be classified as “GTP” in an IMSA race was a Chevrolet-powered BMW M-1 entered by Jim Busby at Road Atlanta in 1980. Seen here at Riverside, the car turned out to be a beast to drive and was abandoned the next race weekend at Laguna Seca. Photo: Kurt Oblinger
The Busby March M-1 Chevy dropped out of both the Road Atlanta and Riverside rounds and turned out to be an unholy terror to drive. Busby had a major off at Laguna Seca in Saturday practice the week after Riverside. The car scared him so much that he threw in the towel and purchased a Porsche 935 from Gianpierro Moretti on the spot and raced it at Laguna the next day.
At the inaugural race of the 1981 season, the first prototype GTP car showed up for the 24 Hours of Daytona. Working largely in his own garage, longtime IMSA competitor Del Russo Taylor spent the better part of 1980 marrying a Chevron B19 chassis with an Alfa Romeo V8 engine. Since the Chevron was designed as an open cockpit sports prototype, he used a Corvette rear window as his mandatory front windscreen. To improve safety, a second roll bar was welded into the chassis next to the original. Hand-crafted sheet metal completed the makeshift roof. The result was less than aesthetic, but the car proved the fundamental point of the new rules. Here was a private entrant with ingenuity that assembled a fast prototype using readily available parts.
The first purpose-built GTP car entered in an IMSA event was Del Russo Taylor’s converted Chevron B-19 with an Alfa Romeo engine that first arrived at Daytona in January 1981. It would practice, but not compete in the race. Photo: IMSA Collection/International Motor Racing Research Center
At Daytona, the car was so slow, especially at night, that IMSA reluctantly told Taylor he couldn’t race. Taylor went home, worked some more, and turned up at Sebring six weeks later, where he finished 51st, completing just 72 laps. The car was called an Alfa Chevron for that race, but a Buick V6 was installed for subsequent events. Taylor ended up running the car for several years in the GTP class, at times with impressive speed, including a fifth-place at Mosport and a sixth at Lime Rock in 1982.
“The first time I really got a good look at that car was when we pulled into the paddock at Sears Point and I noticed what looked like the remains of a massive wreck laid out on the cement in a circle about 40 feet wide,” recalled Bishop. “Roger Bailey was with me and he said: “I sure hope no one got hurt in that wreck.” Turned out, it was simply Taylor’s car in pieces, complete with oil stains, in the middle of an engine change”
Just to confuse the matter further of which was the first IMSA GTP car, there was another entry that showed up at Daytona in 1981 that ran either in the GTP or GTX class depending on which story you believe. McLaren Engines in Michigan built a Ford Mustang fitted with a 2.0-liter normally aspirated Cosworth racing engine. Dubbed a “McLaren Mustang,” the car ran on shaved Firestone HPR street tires and contained a few other trick parts like a unique Halibrand Sprint Car quick-change differential and a live rear axle. Firestone sponsored the entry as part of an effort to promote their high-performance street tires. Ford Performance had nothing to do with the effort, according to then team manager Roger Bailey. The original intention was to race the car in the IMSA GTO class but with the non-production-based engine, the car wasn’t eligible for that class.
The McLaren Mustang’s Cosworth-based, four-cylinder engine. Photo: Ed Wheatley (current owner)
The McLaren Mustang at speed at Daytona in 1981. Note the hastily made “GTP” decal on the driver’s door along with the official “IMSA GT” decal. Photo: Ed Wheatley
This is where the two stories diverge. According to IMSA results, the car was listed as a GTX machine, running up against a host of Porsche 935s and tricked-out Corvettes. Yet the team was adamant that the car was run in GTP. The letters “GTP” were painted (or a decal was hastily created) on the driver and passenger side doors in what looked like an official IMSA font but were not put there by IMSA officials. The only official IMSA class sticker on the car was “IMSA GT” on the same doors.
It may be that the team realized that the car didn’t stand much of a chance in the GTX class and concocted a scheme to try to run the car run in GTP since there were no other cars running in GTP at Daytona in 1981. Doing so would guarantee a win for the team. It’s not clear whether IMSA officials noticed or decided to turn a blind eye to the scheme during the event but the car was eventually classified in the final results in “GTX.” The car ran well in the race but an engine change during the night relegated drivers John Morton and Tom Klauser to a 21st-place finish (8th in GTX). After the event, Ford Performance, who had been absent from the whole project beforehand, touted a “win” in GTP in their marketing materials and postcards.
The McLaren Mustang was entered in just one other race at the 12 Hours of Sebring a few weeks later, where it finished 40th after the rear axle seized out on the track, necessitating a replacement rear-end change by driver Tom Klauser and a mechanic who ran out to the car with spare parts once donning a spare John Morton racing suit to skirt the rules about no mechanics touching race cars out on course. After Sebring, the program was abandoned and the car never raced in IMSA again. It is now owned by Ed Wheatley and being restored for vintage racing.
So the answer to the question: “What was the first IMSA GTP car?” is not a simple one but it’s a most interesting topic.
-Mitch Bishop is the son of IMSA founder John Bishop and co-author of “IMSA 1969-1989,” available wherever great books are sold.
The following is an excerpt from “IMSA 1969-1989” that tells the inside story of how IMSA got started and its first 20 glorious years. Available from Octane Press or wherever books are sold.
BMW of North America’s racing group was established in 1975 in an effort to support the company’s growth in the lucrative US performance car market. Unfortunately, the company did not have an IMSA championship to show for the investments in the BMW 3.0 CSL and the turbocharged BMW 320i. With just one or two cars pitted against a host of Porsches, the odds were not in their favor. The tube frame M-1 Procar did crush the GTO competition in 1981 but was underpowered in IMSA’s top GT Prototype (GTP) class.
Something had to be done to narrow the gap. Former SCCA executive Jim Patterson, who took over the BMW North America racing program in 1978, saw the newly minted IMSA GTP rules in 1980 as a way to get back in the game. Working with partner March Engineering, a unique new prototype was unveiled in early 1981 that would become the basis for a long, successful supply of GTP cars to the IMSA field from the British company.
The BMW M1/C debuted at Riverside in April 1981. The March chassis featured a modern aluminum monocoque that was mated to a normally aspirated 3.5-liter BMW engine. The team would upgrade to a 2.0-liter turbocharged motor later in the year. Photo: Don Hodgdon
Designed by French aerodynamics expert Max Sardou and BMW engineer Raine Bratenstein, the car was dubbed the BMW M-1/C. It was built around a March Engineering aluminum monocoque and featured two distinctive pontoons at the front that were designed to channel airflow to both the radiators and twin ground-effects tunnels for maximum downforce. The car was initially fitted with a 3.5-liter, six-cylinder, normally aspirated BMW engine, and entered for the first time at the Riverside 6 Hours in April 1981 with David Hobbs and European endurance veteran Marc Surer at the wheel. Featuring sponsorship livery from Kenwood audio, the pair finished a credible sixth place, albeit eleven laps down to the winning 935 piloted by Fitzpatrick and Busby.
The lone BMW M1/C is swamped by a host of Porsche 935s at the start of the 1981 Riverside Camel GT race. The M1/C would go on to finish sixth, eleven laps down from the winning Porsche 935 of John Fitzpatrick/Jim Busby (#1). Photo: Don Hodgdon
A week later at Laguna Seca, Hobbs placed sixth again, this time one lap down to the new Lola T-600 with Brian Redman at the wheel. Although down on power, Hobbs managed to put the car on the front row at both Lime Rock and Mid-Ohio. The first few races proved the M-1/C had real potential and the decision was made to further develop the chassis and engine. The long-term plan was to install the 1.5-liter turbocharged BMW motor being developed for Formula One, but that engine wasn’t ready and would never be used in the March. Instead, the team force-fit the same turbocharged 2.0-liter, four-cylinder engine that had been used successfully in the McLaren-engineered BMW 320i program. Since the M-1/C had not been designed for that power plant, it required a cooling workaround for a motor that produced 600 to 675bhp with the boost turned up.
Results were mixed after the change. The new engine debuted at Sears Point in August. The car was fast and competitive, but ultimately unreliable. A fourth place at Portland would turn out to be the team’s best finish. Despite stating long-term commitments early on, BMW again left IMSA racing at the end of the year, this time to focus on its Formula One program.
Even with this setback, March Engineering took what it had learned from the M-1/C experience and produced a viable, stable GTP customer car for 1982, dubbed the 82G, that was designed by Gordon Coppuck. The first two customer March 82Gs appeared in January for the 24 Hours of Daytona. One of them was a Chevrolet V8-powered version driven by Bobby Rahal and Jim Trueman and fielded by Garretson Enterprises. Rahal would campaign the car in later rounds with Michelob backing.
The first March 82G customer car was fielded by the Garretson team at Daytona in January 1982. Photo: Bob Harmeyer
The other March was campaigned by Dave Cowart and Kenper Miller’s Red Lobster team. After winning the 1981 GTO championship in the dominant BMW M-1, the team commissioned an 82G from the March factory with the now well-tested 3.5-liter BMW M-1 engine. The distinctive twin pontoons of the March turned out to be a perfect canvas for two Red Lobster claws, a design that became iconic almost instantly. Unfortunately, the normally aspirated BMW engine was no match for the Chevy V8 or Porsche 935s, and for 1983 the team campaigned with Porsche 935 turbo power, only to suffer from overheating issues. The team took the midsummer Daytona race off in 1983 and came back later in the year with Holbert’s second March 83G powered by a Chevy V8.
The twin pontoons of the March 82/3G were ideally suited for the paint scheme of the Red Lobster team, pictured here in 1983 at Daytona, leading the similar Porsche-powered March of Al Holbert. Photo: Richard Bryant
The biggest news of the 1983 season was the return of Al Holbert, who had been pursuing Indy Car and Can-Am glory. Holbert started the season by sharing Bruce Leven’s Bayside Disposal 935 with Hurley Haywood at Daytona and Sebring. But his main focus was on a CRC Chemicals–sponsored March 83G, initially fitted with a small-block Chevy V8. Holbert won with the car the first time it was entered, at the inaugural, but rain shortened, Grand Prix of Miami. After skipping the Road Atlanta round, Holbert finished second at Riverside and won Laguna Seca, after which he sold the car to Kenper Miller and Dave Cowart’s Red Lobster team.
Holbert had another ace up his sleeve: a brand-new March 83G, this time fitted with an ANDIAL-prepared Porsche 934 single-turbo engine. Despite skipping the Mid-Ohio and mid-summer Daytona events, Holbert easily took the 1983 Camel GT title by winning with the new Porsche-powered car four times and scoring points in another seven races.
Al Holbert’s triumphant return to IMSA competition in 1983 came at the wheel of a March 83G fitted with small block Chevy V8, shown here at Riverside. He later switched to a new March 83G chassis fitted with a single turbo Porsche 934 motor and won the 1983 Camel GT championship. Photo: Kurt Oblinger
One of the prettiest GTP cars of the era, the ex-Holbert Racing Porsche-powered Kreepy Krauly March 83G of Sarel Van der Merwe, Tony Martin, and Graham Duxbury, won the 24 Hours of Daytona in 1984, pictured here at Riverside in the 1984 season. Photo: Kurt Oblinger
The Blue Thunder Marches of Bill Whittington and Randy Lanier, sponsored by Apache Powerboats, dominated the 1984 Camel GT season with six wins, including one here at Watkins Glen, giving the title to Lanier. Photo: Whit Bazemore
With the introduction of the Porsche 962 into the Camel GT Series in 1984, it wouldn’t take long for Porsche to once again dominate U.S. sports car racing. The 1984 championship in the hands of Randy Lanier driving a Chevy-March would turn out to be the last for a March-based car in the series. But not without a fight.
BMW decided to renew its Camel GT program by entering a March 86G chassis for David Hobbs and John Watson in the 1985 season-ending race at Daytona. As before with the 320i program, McLaren North America prepared the cars and ran the team. By this time, BMW’s 1.5-liter turbocharged Formula One engine was well developed and reliable. It was the same engine used by Nelson Piquet to secure the 1983 Formula One World Championship. It was adapted in a 2.0-liter form for the March 86G, the first prototype designed entirely using computer-aided design equipment. Power output was a reputed 1,100bhp with the boost turned up.
A second car for John Andretti and Davy Jones was built early in 1986, but during testing at Road Atlanta, it was destroyed in a fire caused by a fuel line that had been loosened by an engine vibration. The same vibration caused a serious, end-over-end crash in practice at Sebring when the rear cowling flew off, destroying a second tub, and forcing the team to withdraw.
Given the teething issues and destroyed cars, Bob Riley and a host of all-stars were brought in to help sort things out. After working flat out, the team turned the BMW-March into a very fast but still inconsistent car. The team skipped a few races during the 1986 season, but the car’s outright speed was evident whenever it showed up. After winning the pole at Road America, Jones survived a horrific high-speed crash in the race just after the kink in the backstretch when he put two wheels off in the grass on driver’s left. Bad luck and mistakes seemed to dog the team.
The BMW March 86G was a generation ahead of the rest in terms of aerodynamic grip and raw speed in 1986. Reliability issues kept it from doing well much of the season. Photo: Bob Harmeyer
However, the team’s triumphant moment arrived in one spectacular win at Watkins Glen with Andretti and Jones at the wheel. The two BMWs started on the front row and the winning car lapped almost everyone else in the field. In spite of the promising result and the car getting faster without direct factory support from Germany, BMW once again withdrew from IMSA after the Daytona finale at the end of 1986. David Hobbs lamented the decision, saying, “We could have cleaned the table with that car in 1987, it was probably the fastest prototype I ever drove.” Two of the March 86G chassis were sold to Gianpiero Moretti, who installed Buick V6s (one was a turbocharged 3.0-liter and another was a 4.5-liter normally aspirated motor) and raced them the following year.
The BMW March team scored its most impressive weekend at Watkins Glen, with both cars on the front row and John Andretti/Davy Jones taking the overall win in convincing fashion. Photo: Tony Mezzacca
When BMW canceled its IMSA GTP program at the end of 1986, Gianpiero Moretti purchased the March 86G chassis and installed turbo-powered Buicks for the 1987 season. He co-drove here at Sears Point with Whitney Ganz. Photo: Richard Bryant