Feature three-piece assembled flywheels with shaftsDo not require any motor case modification4-1/2'' stroke103'' stock motors or motors with factory 95'' kits require piston kit only stock or S&S cylinder heads can be usedStock cylinders will require boring to 3.875''Made in the USAFuel-injected motors will require recalibration of the fuel-injection system.This project requires a skilled technician. It is the responsibility of the person assembling the parts to check all clearances and assembly specifications.