Sierra Marine Parts Catalog

978 CYLINDER HEAD ASSEMBLIES All cylinder heads are new castings and complete assemblies with new - stainless steel valves, hardened steel exhaust seats, valve springs, valve locks, and retainers. All GM cylinder heads utilize high performance screw-in rocker arm studs in place of factory press in rocker arm studs. 18-4485 CYLINDER HEAD ASSEMBLY Fits: 5.7L V-8 GM (1987-95) with press in rocker arm studs with 12 intake manifold mounting bolts- (4 inside intake manifold bolts at 23 degrees), center mount valve covers 18-4486 CYLINDER HEAD ASSEMBLY Fits: 5.7L V-8 GM Vortec (1996-Up) with press in rocker arm studs with 8 intake manifold mounting bolts, composite valve cover 18-4489 CYLINDER HEAD ASSEMBLY Fits: 2.5L/3.0L GM (1968-95) (non MerCruiser LX models) (1968-95) 18-4491 CYLINDER HEAD ASSEMBLY Replaces 4.3L Vortec V-6 (1996-Up) with screw in rocker arm studs (non-adjustable valve train), 8 intake manifold mounting bolts, center mount valve cover. NOTE: not for use with engines using factory roller rocker arms. 18-4501 CYLINDER HEAD Fits: 5.0L Vortec I/O —VOLVO PENTA - Internal Engine System 18-4501HP CYLINDER HEAD Fits: Vortec GM small block 5.0L Completely assembled with revised runner and combustion chambers. Add 30hp to stock motor with no additional modifications. 18-4486HP CYLINDER HEAD ASSEMBLY Fits: Vortec GM small block 5.7L high performance Completely assembled with revised runner and combustion chambers. Add 30hp to stock motor with no additional modifications.