Skip to content Skip to navigation menu

Cylinder Head


Model # 13476858 | Mfg # 18-4504
Delivery within 2 - 3 weeks.
  • 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 guideplates18-4506
  • Rectangle intake ports GUIDE PLATES
  • Use on factory non-adjustable valve train applications require adjustable rocker arm assemblies such as Sierra's 18-4507
  • Uses Sierra 18-4506 guide plates to utilize factory 5/16" pushrods

Cylinder Head

Type Heads

West Advisor

The West Advisor articles have answered boaters' questions and provided solutions to boating problems for more than 20 years. West Marine has compiled one of the Web's most comprehensive collections of technical boating information articles.