With installed balancer gear. With full wristpin width connecting rods for use with S&S pistons. Comes fully assembled with flywheels; connecting rods; connecting rod bearings; pinion and sprocket shaft. - Heat Treated 4140 Material is harder & more than twice as strong as stock - Stronger assembly eliminates need to weld crankpin - S&S High Strength Connecting Rods are designed with Finite Element Analysis to eliminate weak spots - Full width wristpin connecting rods (requires S&S Performance Pistons) - Balanced for S&S Performance piston weight (1213g) - Perfect for Gear Drive Cams - Consistent balance & precision machining - Capable of higher RPM for more available power! Note: Required for installation of 923194 / 923193 131" (4.250" bore) and S&S 994438/994437 136" (4.320" bore) big bore cylinder and piston kits. Note: Balancer gear is included. See 923271 for identical flywheel assembly without balancer gear.