American Challenge

American Challenge, also known as the All American Challenge, and formally known as the Kelly American Challenge, was a category and set of regulations for grand tourer cars in sports car racing, specifically in the IMSA GT Championship, between 1977 and 1989. Similar to the AAGT class, these cars were All-American, use a maximum of 5 forward gears, and use a steel tube frame (similar to the type used in SCCA Trans-Am Series cars).