In 1964, Pontiac broke a GM rule by putting an engine larger than 330 cubic inches engine into a LeMans and created the muscle car as we know it today. The big 389 was good for 325 hp, 348 in Tri-Power guise. Putting big engines in little cars became the American way and gave birth to several iconic muscle cars in the 1960s and 70s.

Hays bulletproof billet flywheels are developed specifically for the high-RPM punishment of competition use. Steel and aluminum flywheel applications available for many transmission and engine combinations.