S&S heads give great performance, and work with additional upgrades. Kits are fully assembled, and include stainless steel valves and high-lift springs (up to .640 lift). Intake manifold, pistons and gasket kits are sold separately; gasket kits contain head gaskets, base gaskets and exhaust pipe gaskets (rocker box gaskets are not included due to the variety of available rocker box styles). Must reuse stock headbolts. S&S Super Stock piston kits are required and include 10:1 ratio pistons, rings, piston pins and clips (sold separately in pairs). Made in the U.S.A..