1975 IMSA GT Championship season Tags: Motorsport Season.The 1975 Camel GT Challenge season was the 5th season of the IMSA GT Championship auto racing series. The series was for GTO and GTU class Grand tourer racing cars. It began February 1 1975 and ended November 30 1975 after seventeen rounds. series IMSA GT Championship year 1975-01-01T00:00:00+02:00 Learn more... Loading...