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12562920 -Big Block Chevy Rectangle Port Iron Cylinder Head- Complete, 425 Hp 454 & 450 Hp 502

This product may require vehicle validation(s) for proper fitment. Please contact us to confirm correct vehicle fitment and usage.

Pricing: $726.27


12562920 Big Block Chevy Iron Cylinder Head

Gen. VI design head will work on all Mark IV,V & VI engines with the appropriate head gasket. Head gasket used should match the generation series of the block. This cylinder head is very similar in design to the old LS6 cylinder head.


  • 118cc open chamber
  • Rectangular intake ports
  • 3/8" Rocker stud holes- (Use GM part# 12495518 stud kit & 12368085 rocker arms to convert to 7/16" adjustable)- Also requires are part# 14097005 push guide plates guideplates
  • 7/16-14 Accessory holes in end of head (Conventional bib block layout)
  • 2.18" Intake valves- part # 14097045
  • 1.88" Exhaust valves-part # 14097049
  • 1.487" diameter valve springs, 110Lbs @ 1.88" good for .600" lift
  • Retainers & seal kit- part # 12360874
  • Valve stem keepers- 3947880
  • Valve spring shim- 3875916

The above parts are included with each head. Uses conventional 1965-2000 Big block Chevy valve cover bolt pattern.

Application List



Shipping Information

  • Item Requires Shipping
  • 76.0 lbs.
  • W11.1200” x H9.0000” x L23.5000”

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