Cylinder Heads: Additional Required Components Part Number Gaskets (Quantity) Bolts (Quantity) Spark Plug Engine Application 12562920 14097001 (2) OR 12555728 (2) 10141204 (24), 10141205 (8) 19355200 19433157, 19433409 12562926 14097001 (2) OR 12555728 (2) 10141204 (24), 10141205 (8) 19355200 19433157, 19433409 12562925 14097001 (2) OR 12555728 (2) 10141204 (24), 10141205 (8) 19355200 19433157, 19433409 19418910 12363411 (2) 12367779 (1 Kit) 19307141 12499121, 12497323, 19433160 19418909 12555728 (2) 88960333 (16), 88960334 (8) 19307141 19433410 19331430 88961561 (2) 88960333 (16), 88960334 (8) 19354424 12498826, 19331585 19331429 88961561 (2) 88960333 (16), 88960334 (8) 19382850 19331581 CYLINDER HEAD GASKETS Secure sealing between the cylinder heads and the block is a critical component of making reliable horsepower, so Chevrolet Performance puts the same engineering excellence and manufacturing precision into their gaskets, head bolts, and cylinder head studs as the blocks and heads they secure. Big-Block cylinder head gaskets are available in a variety of materials and thicknesses. Piston-to-head clearances should be considered when selecting gaskets. Use Gen V for 1991–1992 applications. Gasket packages contain one gasket unless otherwise specified. Rectangular Port Heads Part Number Description Technical Notes 12363414 Composition Head Gasket – 1965–1990 With pre-flattened copper wire ring and permatorque/blue stripe coating for engines with aluminum heads; Bore sizes between 4.250" and 4.370"; Use with Mark IV (1965–1990) engines only; Compressed thickness is .039" 12363412 Composition Head Gasket – 1991–newer (not shown) For 1991-and-newer Gen V and Gen VI Big-Blocks with aluminum heads and 4.250" to 4.370" bore size; Has pre- flattened wire ring and stainless core, which make it ideal for saltwater marine use; Compressed thickness is .039" 12555728 Head Gasket – 454 Engine (not shown) Head gasket for 1991–2000 Gen V 454 Big-Blocks 12366984 Head Gasket Kit – 502 Engine For all Gen V and Gen VI 502 Big-Blocks with cast-iron heads; Has additional water hole for improved cooling of siamesed cylinder walls; Includes 2 gaskets (right and left) per package; Compressed thickness is .041" 12363411 Composition Head Gasket – 1991–newer (not shown) For Gen V and Gen VI Big-Blocks with aluminum heads and 4.375" to 4.540" bore size; Has pre-flattened wire ring and stainless core, which make it ideal for saltwater marine use; Compressed thickness is .039" 88961561 Head Gasket – 572 Engine With pre-flattened wire ring for all 572 Big-Blocks with either cast-iron or aluminum heads; Compressed thickness is .030" Head Bolts and Studs Part Number Description Technical Notes 12367779 Cylinder Head Bolt Kit (not shown) Universal kit for cast-iron and aluminum Big-Block heads; Includes (8) 7⁄16"-14 x 2.08" bolts P/N 88960334, (24) 7⁄16"-14 x 4.060" bolts P/N 88960333, (8) 7⁄16"-14 x 5.06" bolts P/N 88960332, and (40) hardened washers P/N 14011040; Use part numbers above for replacement parts; Use thread sealant on all Big-Blocks except 502, due to blind bolt holes; not for use on ZZ632 or RSX cylinder heads. VALVES Intake Valves Part Number Valve Size Stem Size Description 12556317 2.190" 3⁄8" Stock replacement valve for Gen V and Gen VI 454 and 502 HO engines 12366986 2.190" 11⁄32" Stainless-steel valve with undercut chrome-plated stems, single-groove design, hardened tips; Used on ZZ454, ZZ427 and the Anniversary Edition 427 crate engines 12366987* 2.250" 11⁄32" Stainless-steel valve with undercut chrome-plated stems, single-groove design, hardened tips; Used on ZZ502 and ZZ572 *Item has been discontinued. See dealer for available stock. Exhaust Valves Part Number Valve Size Stem Size Description 14097049 1.880" 3⁄8" Stock replacement valve for Gen V and Gen VI 454 and 502 HO engines 12366988 1.880" 11⁄32" Stainless-steel valve with undercut chrome-plated stems, single-groove design, hardened tips; Used on ZZ454, ZZ427 and the Anniversary Edition 427 crate engines 88963128 1.880" 11⁄32" Stainless-steel valve with undercut chrome-plated stems, single-groove design, hardened tips; Used on ZZ502 and ZZ572 204 BIG-BLOCK COMPONENTS Head Gasket – 572 Engine Head Gasket Kit – 502 Engine Composition Head Gasket – 1965–1990 Exhaust Valve – 1.880" Intake Valve – 2.250" Additional components required for installation. See chart above.
