Sierra 18-4501 Chevy (GM) 5.0-Liter Vortec Cylinder Head. Valve cover bolts down center, Vortec engines with 8-bolt intake manifold. New casting with new stainless steel valves, hardened steel exhaust seats, new valve springs, valve locks, retainers and screw in rocker arm studs.
Head casting 620 and 12558059, replaces First Mate H-6018. Replaces Mercruiser 938-802556 and 938-802556T. 1-year limited warranty.