Grand Touring Prototype (GTP) is the name of a former classification designated to sports prototypes in sports car racing competing in the IMSA GT Championship, maintained by IMSA between 1981 and 1993. The early cars were based on the almost same identical ruleset as the FIA's Group C category, but eventually evolved into a separate category. It was the successor to the Grand Touring Experimental (GTX) class, which were based on FIA Group 5 and Group 6 cars.
Nissan GTP ZX-Turbo
Eagle HF-98
Jaguar XJR-9
Jaguar XJR-9
Group C was a category of sports car racing introduced by the FIA in 1982 and continuing until 1993, with Group A for touring cars and Group B for GTs.
A sticker on a race car from the 1984 24 Hours of Le Mans, denoting the car is part of the Group C category.
The Porsche 956 was a dominant car in its many factory and customer built forms in the early 1980s.
Jaguar XJR-8 at the Goodwood Festival of Speed, 2008.