Sierra Marine Parts Catalog: High Performance Products
CYLINDER HEAD
� Aluminum cylinder heads sold in pairs only or 454 & 502 cu.
In big-block GM applications.
� Custom engraved with Sierra High-Performance logo
� 320 cc intake runner/119cc exhaust runner
� 2.25 intake/1.88 exhaust stainless steel valves
� 5 angle valve seat cut
� Up to 65HP increase over OE cylinder heads
� Suitable for use on Mark IV, Gen V, & Gen VI GM blocks.
Must use correct corresponding head gaskets
� Std. BBC 7/16" rocker studs and 3/8" diameter pushrod guideplates
� Rectangle intake ports
GUIDE PLATES
� Use on factory non-adjustable valvetrain applications require adjustable rocker arm assemblies such as Sierra's 18-4507
Big-Block GM with 5/16" pushrods
� Use Sierra 18-4506 guide plates to utilize factory 5/16" pushrods
ROCKER ARM ASSEMBLY
ROCKER ARM KIT (4 vALvES)
HEAD BOLT KIT
Replaces: Mercruiser 35329
Big-Block GM
Fits: MCM/MIE Gm V6 & V8(283, 305 & 350 cid) engines
High performance head bolt kit-small block GM
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.
CYLINDER HEAD ASSEMBLY
CYLINDER HEAD ASSEMBLY
Replaces: MerCruiser 938-883490 1
Fits: 5.7L V-8 GM (1969-86) with 12 intake
Fits: 5.7L V-8 GM (1987-95) with press in rocker arm studs with 12 intake manifold
manifold mounting bolts, perimeter mount valve cover
mounting bolts- (4 inside intake manifold bolts at 23 degrees), center mount valve covers
CYLINDER HEAD ASSEMBLY
CYLINDER HEAD ASSEMBLY
Replaces: MerCruiser 938-883297 1,938-803860T
Replaces: MerCruiser 936-5544, 936-810840/986767
Fits: 5.7L V-8 GM Vortec (1996-Up) with press in rocker arm studs with 8 intake
567
Fits: 2.5L/3.0L GM (1968-95) (non MerCruiser LX models) (1968-95)
manifold mounting bolts, composite valve cover