PRW flywheels are the choice of 5 out of 6 winning engine builders at the engine masters challenge four years running. PRW flywheels are CAD engineered, precision CNC machined to strict tolerances, balanced, and carefully inspected throughout the manufacturing process. The forgings are 1045 billet steel and SFI certified. Most external balance applications feature removable counterweights. Requires high performance clutch. C-Track Spec.