IMSA GT Championship - History

History

The series was founded in 1969 by John Bishop and Bill France, Sr., and racing debuted in 1971. It was originally aimed at two of FIA's stock car categories running at two different classes, the GT (Group 3 and 4) and Touring (Group 1 and 2) cars. The first race was held at Virginia International Raceway; it was an unexpected hit with both the drivers and a handful of spectators who attended.

For the following year, IMSA founder John Bishop brought in sponsor R. J. Reynolds and in 1975, introduced a new category called All American Grand Touring (AAGT). In 1977, the series would go through a series of major changes. IMSA permitted turbocharged cars for the first time as well as introducing a new category called GTX for cars based on the Group 5 rules. In 1981, after Bishop decided to not follow FIA's newly introduced Group C rules, so he introduced the GTP class for sports prototypes. In 1989, Bishop sold off his organization. After a period of decline in the early 1990s, the Worlds Sports car category was introduced in 1993 to replace the GTP category in 1994.

After a period of multiple ownerships, the organization was eventually renamed Professional Sports Car Racing (PSCR). In 1999, PSCR decided to drop their own championship in order to sanction a new American Le Mans Series. Despite various names, the GT series was known commonly as the IMSA series as it had been the organization's dominant series.