S&S 3-Piece Flywheels for Twin Cams

Vast improvement over stock flywheels, which shift out of true under heavy loads. Heat-treated 4140 material is 114% stronger than stock, eliminates thrust washer. Larger 1.671″ crankpin, increased cross-sectional area for increased crank-pin clamping force. No welding required. Integral mainshafts, truer flywheels and less vibration.