Made of high-strength forged steel and designed for stock and high-performance custom applications Special keyed 6? large diameter tapered sprocket shaft that provides more contact area for increased strength Standard S&S tapered crankpin and pinion shaft are used for ease-of-service 8-1/2" diameter with 4-1/4" or 4-5/8" stroke Kits come fully assembled, trued and balanced to stock H-D 80" or 96" pistons Include flywheel, crankpin and connecting rods Made in the U.S.A.. FLYWHEEL 4.25"STRK 95-98