Mark Donohue contacted Charlie Kemp in 1975 about being teammates racing two Monzas in IMSA. The project went forward until Mark's death. Ron Fournier at KarKraft had begun the project. Kemp changed it to a Mustang. Bob Riley engineered it to Kemp's plan. Jack Roush built his first road racing engine at 585 horsepower. The car was delivered for the 1976 Daytona 24 Hour having never turned a wheel. IMSA declared it illegal but Bill France Sr. intervened. Sam Posey did the first drive. He said 'It is really fast but is scary handling!' After tweaking the car, Kemp broke the lap record and was pole sitter at Road Atlanta. Pete Hood built the second engine with 635 horsepower. Depending on gear ratio, 0-60 mph time was 3.8 seconds and clocked top speed at Daytona was 212 mph. The radical design was later used in Roush's IMSA project.