M-6375-G46 (8-bolt). The manual transmission flywheels listed below fit 4.6L SOHC/DOHC and Cobra engine applications. They are dimensionally the same as stock and have the same zero-balance specification as stock flywheels. The nodular iron units are stronger and have increased RPM capability. The billet steel units have even higher RPM capability and meets SFI specification 1.1. .6L engines may have 6 or 8 bolts to attach to the crankshaft. Check the engine code before ordering. Romeo-built engines have 6 bolts and Windsor-built engines have 8 bolts. All Cobra engines have 8 bolts. The 8th character in the VIN is (X) for Windsor engine plant or (W) for Romeo engine plant.