For the 1973 Can-Am championship season, Porsche built the most powerful car to ever compete in a sports race, the 917/30. Derived from the 917/10, the 917/30 had a 5.4-liter turbo engine whose power exceeded 1100 horsepower. It was distinguished from the 917/10 by a longer wheelbase, while the front track was wider and the rear narrower. The 917/30 dominated the championship with American driver Mark Donohue. The latest exploit of the 917/30 was a speed record obtained in 1975 at Talladega, again with Donohue at the wheel, which set an average of 355.846 km / h.