Fastback, feature races were short, 25 laps on a quarter to half mile track depending on venue, + a 10 lap heat race and practice laps. Engines didn't have to last a hundred miles max. It was my brothers belief that an engine runs best just before it blows up. He would rebuild the engine for every race, with used pistons, and his engines smoked a bit to, enough that other drivers stayed clear, strategy worked, track champion at local track, won over half the races. We also crossed the border to race at St. Pie Quebec, 1.3 mile road course & 1/4 mile oval. When we raced the road course, we had to change an engine on a pit stop, still came in top 5