Open Menu
Open Menu

IMSA, the International Motor Sport Association, celebrates its golden anniversary

Published in

John Bishop (L) with Bill France Sr. at Daytona International Raceway. Photos courtesy IMSA.

By the time John Bishop resigned as executive director of the Sports Car Club of America in 1969, he’d amassed over a decade of experience in the management of amateur and professional road racing. With backing from NASCAR’s Bill France Sr., Bishop applied his background to the formation of a new road-racing series — the International Motor Sports Association, or IMSA — that would go on to reshape motorsports in North America and beyond. This year, IMSA turns 50, and the organization will be celebrating this achievement throughout the 2019 season.

Bill France understood that his primary product — NASCAR — did not and could not appeal to those who preferred watching sports cars and formula cars race on road courses. Bishop, who’d helped to develop the United States Road Racing Championship, Trans-Am and Can-Am series during his time with the SCCA, presented France with the opportunity he’d been seeking. France fronted the majority of the funding needed to launch IMSA, and in return took 75-percent ownership of the series. Bishop held the remaining 25 percent, but was also given sole oversight of the organization, a luxury he did not enjoy with the SCCA.

IMSA’s first race was held in October 1969 at Pocono Raceway in Pennsylvania, drawing 348 spectators to watch Formula Vees and Formula Fords compete for a $3,000 purse. The SCCA reportedly flexed its muscle and attempted to block the event without success, but IMSA was asked to pay a $10,000 surcharge in the track rental fee. Undaunted, IMSA scheduled another 10 formula car races for the coming year.

By the end of the 1970 season, however, it was clear that IMSA could not survive by hosting single-seater racing alone. For 1971, Bishop planned a six-race series that would feature sports cars from FIA’s Group 2 and Group 4. To further level the playing field, IMSA would run four classes — GTO, for grand touring cars powered by engines over 2.5 liters in displacement; GTU, for cars with engines smaller than or equal to 2.5 liters; TO, for touring cars with 2.5-liter or larger engines; and TU, for touring cars with 2.5-liter or smaller engines.

A Brumos GTX Porsche leads the field at Road America in 1979. Photo by Dan R. Boyd, courtesy IMSA.

The first race for what would become the IMSA GT Championship took place at Virginia International Raceway and was a hit among drivers and fans alike. Peter Gregg and Hurley Haywood, driving a Porsche 914-6, would go on to earn the 1971 season GTU championship, while Dave Heinz captured the GTO crown behind the wheel of a Chevrolet Corvette. In the TO class, Chevrolet’s Camaro bested AMC’s Javelin for the manufacturer’s title, while Austin won the TU manufacturer’s championship.

In 1971, the R.J. Reynolds Tobacco Company signed on as a sponsor, creating the Camel GT series. With money for advertising and promotion, the series quickly grew in popularity, adding more fans year upon year. By 1977, both TO and TU classes were phased out, and in 1978 the GTX class debuted for FIA Group 5 cars, which were production-based but heavily modified for racing. The class soldiered on until 1982, when it was renamed GTP and opened up to include both GTX cars and prototypes, manufacturer-backed, purpose-built racing cars that became the hallmark of IMSA racing into the early 1990s.

While the Porsche 962s, Nissan GTP ZX-Turbos, and Toyota Eagles were the big draw for fans, IMSA also expanded to include the Camel Lights Prototypes, the American GT class and even the Kelly American Challenge for American stock cars. As the 1980s came to a close, IMSA offered a class for virtually every type of car, from production sports cars through single-seat formula cars through money-is-no-object prototypes, but change was on the horizon.

Prototypes at Road America in 1985. Photo by Dan R. Boyd, courtesy IMSA.

In 1989, Bishop and his wife Peggy sold IMSA to Mike Cone and Jeff Parker, who already owned the IMSA Grand Prix of St. Petersburg. Five years later, in 1994, IMSA sold again, this time to Charles Slater, a founding partner of medical equipment supplier Symbiosis Corporation and IMSA GTU driver. It was a period of radical change in racing, as a contracting global economy prompted automakers to abandon racing for self-preservation. To attract more privateers back to the sport, IMSA replaced the GTP class with a new category called World Sports Cars, which were open-cockpit racing cars powered by production engines to minimize costs.

Nothing lasts forever, and in 1996 Slater sold IMSA to the International Motor Sports Group, consisting of Roberto Muller, the former co-president of Reebok, and Andy Evans, an investor in an Indy Car team and an owner-driver in the IMSA WSC class. For the 1997 season, the IMSA name was changed to Professional SportsCar Racing, prompting the SCCA to go on the attack, reviving the United States Road Racing Championship for the 1998 season.

A Corvette prototype chased by a Porsche 962.

It was more than an idle threat, since quite a few big names were affiliated with the SCCA effort, including John Bishop, Roger Penske, Skip Barber and Don Panoz. At issue was who’d control the rules for endurance racing in the United States: The SCCA and its backers preferred to organize events free and clear of international interference, while Professional SportsCar Racing looked to standardize rules with international sanctioning bodies.

When the SCCA’s efforts stumbled, Don Panoz seized the opportunity. Working with the Automobile Club de L’Ouest (the organizers of the 24 Hours of Le Mans), Panoz created a 10-hour race dubbed “Petit Le Mans” for Road Atlanta, a track Panoz owned. The inaugural 1998 running proved a success, so Panoz announced the formation of the American Le Mans Series (ALMS) for 1999, to be sanctioned by Professional SportsCar Racing.

A Jaguar GTP leads the field at the 1989 24 Hours of Daytona. Photo by Dan R. Boyd, courtesy IMSA.

The revival of the United States Road Racing Championship was cancelled midway through the 1999 season, prompting the France family to organize a new series for sports car racing in North America, called the Grand American Road Racing Association. This group took more of a grass-roots approach to racing in an effort to contain costs, but it soon became clear that North America could not indefinitely sustain two road racing organizations with similar products.

In 2001, the seeds of reunification were planted when Evans sold Professional SportsCar Racing to Don Panoz, who wasted no time in returning the sanctioning body’s name back to the International Motor Sport Association. Under this familiar banner, IMSA would serve as the sanctioning body for the ALMS, Prototype Lites, Star Mazda, GT3 Cup Challenge and the Panoz GT Pro series.

In 2012, talks began to unify the ALMS and the Grand American Road Racing Association into a single entity, and in September of that year the merger was made official beginning with the 2014 season. IMSA would be the sanctioning body, and fans would no longer need to split their allegiance between two series, each with exclusive access to premier tracks and events.

Daytona 2019 – the Chip Ganassi Racing Ford GT and Porsche 911 GSR decked out in throwback liveries.

Today, IMSA is healthier than ever, as demonstrated by the appeal (to fans and drivers alike) of its season-opening Rolex 24 at Daytona. In celebration of its 50th anniversary, numerous teams participated in throwback liveries, including Porsche (which ran with a Brumos Porsche color scheme), CORE autosport (which campaigned its DPi car in classic Nissan colors) and Acura (which used the familiar orange and white Comptech colors on its number 43 NSX GT3 car and on its Team Penske DPi cars). Look for IMSA to celebrate four cornerstones of its success – including “Drivers and Teams,” “Tracks,” “Manufacturers,” and “Fans” throughout the 2019 season.

For details on special events planned for upcoming races (including the 12 Hours of Sebring, taking place on March 13-16) or to view 50th anniversary videos , visit