DRCE PRO STOCK HEADS
Six-time NHRA Pro Stock world champion, Warren “The Professor” Johnson, runs DRCE, why don’t you? The GM Performance DRCE 2 aluminum cylinder head was specifically designed for DRCE 2 block P/N 24502572 and intended for NHRA Drag Racing
Pro Stock competition applications. Complies with rule for 500 cubic inch engines with 4.900" cylinder bore spacing. Special features include: high capacity water jackets, symmetrical port layout, ample wall material for custom porting, thick deck surface (7/8") to facilitate angle milling, and reduced weight casting to minimize CNC machine time. Typical CNC-prepared head without valves or valve train weighs approximately 40 pounds. DRCE Pro Stock Race Head Technical Notes:
• T355-T7M Aluminum
• 7/8" thick decks allow for angle milling or heavy flat milling
• High capacity self-purging water jackets
• Symmetrical intake port layout
• Intake and exhaust ports are extremely small “peanut ports”
• Requires professional porting and machining
• Complies with NHRA Pro Stock 500 CID, 4.900" bore spacing rules
• Custom, aftermarket rocker arm assemblies required A. 24502585
DRCE 2 Raw Aluminum Cylinder Head
• Raw aluminum casting, not machined
• Accommodates 10–14 x 5 intake and 5–9 x 2.5 exhaust valve angles
• Made to work on DRCE 2 block P/N 24502572  B. 25534404
DRCE 3 Aluminum Cylinder Head Casting
• Raw aluminum casting, not machined
• Newest design DRCE—rocker arm mounting pads and valve spring seat pads allow greater flexibility with valve angles and locations than DRCE 2
• Made to work on DRCE 3 block P/N 25534403 & DRCE 2 P/N 24502572 
25534405
Semi-Finished DRCE 3 Aluminum Cylinder Head (not shown)
• Starts out as un-machined head P/N 25534404
• Deck, end faces, and valve cover rail with tapped mounting holes are machined
• Tapped water jacket access holes provide opportunity to plumb water near exhaust ports
• Head includes eight #8 A/N plugs and one #16 A/N plug 25534387
DRCE 3 Water Jacket Plug (not shown)
• For ends of DRCE 3 cylinder head casting P/N 25534404
• Aluminum #16 A/N with internal hex for Allen wrench
• Includes O-ring
• Sold individually; use two per head. 25534388
DRCE 3 Water Jacket Plug (not shown)
• For water jacket access holes of DRCE 3 cylinder head casting P/N 25534404
• Aluminum #8 A/N with internal hex for Allen wrench
• Includes O-ring
• Sold individually; use eight per head. BIG-BLOCK CYLINDER HEADS
Part Description Casting Material Port Port Valve Chbr Int Exh Exh Plug Heat Rocker Notes Page Number Number Size Type Angle CC's Vlv Vlv Port Type Riser Stud Number
12562920 Gen 5,6 BBC 12562934 Iron 325 Rect BBC 118 2.18 1.88 Square Std Yes Screw-in Ass'd 2925's 250
12562925 Gen 5,6 BBC 12562934 Iron 325 Rect BBC 118 2.18 1.88 Square Std Yes Screw-in 7/16 accy holes 250
12562926 Gen 5,6 BBC 12562934 Iron 325 Rect BBC 118 2.18 1.88 Square Std Yes Screw-in 3/8 accy holes 250
12552888 Gen 5,6 BBC 10114156 Iron — Round BBC 118 2.07 1.72 Square Std Yes Screw-in HT 502 head N/S
12363390 Oval alum 12363391 Alum 290 Oval BBC 110 2.25 1.88 Square Std No Screw-in Semi-open, oval port 251
12363392 Oval alum 12363391 Alum 290 Oval BBC 110 2.19 1.88 Square Std No Screw-in Semi-open, oval port 251
12363399 Oval alum 12363391 Alum 290 Oval BBC 110 2.19 1.88 Square Std No Screw-in Bare 3392 251
12363408 NHRA L88 12363401 Alum 315 Rect BBC 118 2.19 1.88 Square Std No Screw-in Bare, NHRA legal 252
12363400 Rect alum 12363401 Alum 315 Rect BBC 118 2.25 1.88 Square Std No Screw-in — 252
12363410 Rect alum 12363401 Alum 315 Rect BBC 118 2.25 1.88 Square Std No Screw-in Bare 3400 252
12363425 BBC Bowtie 14044861 Alum 380 Rect BBC 115 2.19 1.88 Square Std No Screw-in Bare, raised int/exh 253
14044876 BBC Bowtie 14044861 Alum 380 Rect BBC 115 2.19 1.88 Square Std No Screw-in Unmach 12363425 N/S
12499255 572/620 — Alum 380 Rect BBC 118 2.25 1.88 Square Std No Screw-in ZZ572/620 252
88961160 572/720 — Alum 380 Rect BBC 118 2.25 1.88 Square Std No Screw-in ZZ572/720R 252
10051129 Prostock BBC — Alum 400 — Special 72 — — Square — No Shaft Unmachined 1128 N/S
22530959 DRCE 1 — Alum — — DRCE 1 — — — DRCE — No Shaft Pro Stock - raw N/S
24502585 DRCE 2 — Alum — Peanut DRCE 2 — — — DRCE — No Shaft Pro Stock - raw 254
25534404 DRCE 3 — Alum — Peanut DRCE 2 — — — DRCE — No Shaft Pro Stock - raw 254
25534405 DRCE 3 — Alum — Peanut DRCE 3 — — — DRCE — No Shaft Semi-finished 254 CYLINDER HEAD GASKETS & HEAD BOLTS GM Performance Parts cylinder head gaskets, cylinder head bolts, and cylinder head studs are the finest quality parts available to ensure a secure seal between the engine block and cylinder heads. Gasket packages contain one gasket unless otherwise specified. Order two per engine. Big-block cylinder head gaskets are available in a variety of materials and thicknesses. Keep engine’s intended usage and minimum piston-to-head clearance in mind when selecting gaskets. Use Gen V for 1991–1992 applications.
C. 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 0.039" 10159507
Composition Head Gasket (1965 –1990) (not shown)
• For Mark IV 1965–1990 big-block with 4.440" cylinder bores
• No sealer required
• Re-torque after engine is first run
• Use with Mark IV (1965–1990) engines only
• Compressed thickness is 0.039" 12363413
Composition Head Gasket (1965 –1990) (not shown)
• With pre-flattened copper wire ring and permatorque/ blue stripe coating for engines with aluminum heads and bore sizes 4.375" to 4.540"
• Use with Mark IV
(1965–1990) engines only
• Compressed thickness is 0.041" 12363412
Composition Head Gasket (1991–Newer) (not shown)
• For 1991-and-newer Gen V and VI big-block with aluminum heads and 4.250" to 4.370" bore size
• Has pre-flattened wire ring and stainless core which makes it ideal for saltwater marine use
• Compressed thickness is 0.039"
12555728
Head Gasket, 454 Engine (not shown)
• Head gasket for 1991–2000 Gen V
454 big-block A. 12366984
Head Gasket Kit, 502 Engine
• For all Gen V and Gen VI 502 big-block with cast iron heads
• Has additional water hole for improved cooling of siamesed cylinder walls
• Includes two gaskets (right and left) per package
• Compressed thickness is 0.041"
12363411
Composition Head Gasket (1991–Newer) (not shown)
• For Gen V and VI
big-block with aluminum heads and 4.375" to 4.540" bore size
• Has pre-flattened wire ring and stainless core which makes it ideal for saltwater marine use
• Compressed thickness is 0.039"
B. 88961561
Head Gasket, 572 Engine
• With pre-flattened wire ring for all 572 big-block with either cast iron or aluminum heads
• Compressed thickness is 0.030" 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 4.06" bolts P/N 88960333, (8) 7/16-14 x 5.06" bolts P/N 12367329, and (40) hardened washers P/N 14011040
• Use part numbers above for replacement parts
• Use thread sealant on all big-block except 502 due to blind bolt holes 3899696
Hardened Washer (not shown)
• 0.45" I.D. x 0.86" O.D.; sold individually
C. 3942410
Head Stud Nut
• Magnafluxed 1038 steel 7/16-20 hex head nut; sold individually D. 14044866
Head Stud Nut
• Magnafluxed 4037 steel 7/16-20 12-point nut; sold individually | 
