The International Motor Sports Association (IMSA) was founded in 1969 by John Bishop with the assistance of NASCAR President Bill France, Sr. Some say that the formation of IMSA was the result of the Sports Car Club of America (SCCA) moving their Runoffs (The Olympics of Racing) away from the NASCAR-owned Daytona Motor Speedway to Road Atlanta in 1969.
Many amateur road racers wanted to be able to race for money — a common practice for many of the lower ranks of circle-track racers. However, SCCA had a policy that discouraged amateurs from racing professionally.
The first IMSA-sanctioned race was at Pocono International Raceway in October 1969. This Formula Ford and Formula Vee event paid $3,000. In 1971, IMSA presented a six-race series for FIA Group 2 and Group 4 sports cars. That series became the IMSA GT Series. The R.J. Reynolds Tobacco Company began sponsoring what became Camel GT in 1972. The series grew to include prototype sports cars. In the 1980s, the IMSA prototypes attracted manufacturers like Porsche, Jaguar and Nissan to compete on tracks in the U.S.
Many of these cars featured turbocharged engines with more than 800 hp. Also, many of the prototypes featured full-length aerodynamic tunnels that could generate huge amounts of downforce. These vehicles were purebred racing cars.
By the late 1980s, however, the series was fighting many challenges caused by the introduction of new technologies. These technologies were expensive and only the factory teams could afford systems like ABS, all-wheel-drive and turbocharged engines that exceeded 1,000 hp. This chasm forced out many privateer teams that defected from SCCA to race in the IMSA.