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2006 GM Chevy Big-Block Quick Reference Chart

GM PRODUCTION-BASED CAST IRON block
Part Casting Deck F Pump Cyl Bore Main Main Blt Cap Crank Oiling Seal Max Weight Max Usage Page Number Number Height Boss Wall Range Bolt Degree Material Jnl Dia. Type Stroke (lbs) HP Number
12561353 — 9.800" Yes Open 4.250"– 4.310" 4 Straight Cast Iron 2.75" Wet 1 pc 4.25" — — Street 241
10237292 — 9.800" No Siamese 4.470"– 4.500" 4 Straight Cast Iron 2.75" Wet 1 pc 4.25" 269 700 Mod 241

GM BOWTIE CAST IRON BIG-block
Part Casting Deck F Pump Cyl Bore Main Main Blt Cap Crank Oiling Seal Max Weight Max Usage Page Number Number Height Boss Wall Range Bolt Degree Material Jnl Dia. Type Stroke (lbs) HP Number
25534362 24502504A 9.800" Yes Siamese 4.494"– 4.600" 4 16 Nodular 2.75" Wet 2 pc 4.50" 258 800 Sport 242
25534363 24502504A 9.800" Yes Siamese 4.494"– 4.600" 4 16 Nodular 2.75" Wet 1 pc 4.50" 258 800 Sport 24225534364 24502506A 10.200" Yes Siamese 4.494"– 4.600" 4 16 Nodular 2.75" Wet 1 pc 4.50" 263 800 Sport 243
25534367 24502506A 10.200" Yes Siamese 4.494"– 4.600" 4 16 Nodular 2.75" Wet 2 pc 4.50" 263 800 Sport 243
25534368 24502506A 10.200" Yes Siamese 4.560"– 4.600" 4 16 Nodular 2.75" Wet 1 pc 4.50" 263 800 Sport 243
24502500 24502504A 9.800" Yes Siamese 4.240"– 4.600" 4 16 8620 steel 2.75" Wet 2 pc 4.50" 281 1200 Pro 245
24502502 24502506A 10.200" Yes Siamese 4.240"– 4.600" 4 16 8620 steel 2.75" Wet 2 pc 4.50" 296 1200 Pro 245

GM DRCE block
Part Casting Deck F Pump Cyl Bore Main Main Blt Cap Crank Oiling Seal Max Weight Max Usage Page Number Number Height Boss Wall Range Bolt Degree Material Jnl Dia. Type Stroke (lbs) HP Number
24502572 1A626 9.525" No Siamese 4.500"– 4.700" 4 16 8620 steel 2.75" Dry 2 pc 4.60" 255 1400+ Pro 246
12480026 1A629 9.525" No Siamese 4.500"– 4.700" 4 16 8620 steel 2.75" Dry 2 pc 4.60" 255 1400+ Pro 246
25534403 Grey 9.25"–9.0" No Siamese 4.590"– 4.700" 4 22 4140 steel 2.50" Dry 2 pc 4.60" N/A 1400+ Pro 247
25534406 CG 9.25"–9.0" No Siamese 4.590"– 4.700" 4 22 4140 steel 2.50" Dry 2 pc 4.60" N/A 1400+ Pro 247

GM ALUMINUM ZL1 BLOCK
Part Casting Deck F Pump Cyl Bore Main Main Blt Cap Crank Oiling Seal Max Weight Max Usage Page Number Number Height Boss Wall Range Bolt Degree Material Jnl Dia. Type Stroke (lbs) HP Number
12370850 3946053 9.800" Yes Siamese 4.240"– 4.300" 4 16 8620 steel 2.75" Wet 2 pc 4.38" 110 650 Pro 244

GM PRODUCTION-BASED block

The GM Performance Parts production-based block are the right choice for street car rebuilds or to start your own mild engine project. They come in the same dimensions that you are already familiar with and are produced to the high level of quality that GM is famous for. Remember, these are brand new castings that are machined to our exacting tolerances. These block are designed for street engines that demand good strength and a high level of durability. One of these block has siamesed cylinder walls1 and both have four-bolt main caps2 that are secured by Grade 8 bolts. Both block have a 9.800" deck height. These production-based block are a great foundation for your serious street car or drag car that makes between 350 and 500 horsepower.

Production-Based Block Technical Notes:
• Can accept Mark IV, Gen V– VI iron and aluminum cylinder heads
• Require Gen V or Gen VI design one-piece rear main seal oil pans
• 9.800" standard deck height
• Machined for hydraulic roller or flat tappets
See chart on page 240 for complete specifications.

12561353
427/454 Bare Block
• Production type cast iron 4-bolt block
• 4.25" rough finished bore
• 4.31" max bore (non-siamese bore)
• Machined mechanical fuel pump pad

10237292
502 Gen VI Bare Block
• Production type cast iron 4-bolt block
• Siamesed cylinder walls
• 4.47" rough finished bore
• 4.500" max bore (siamese)
• No provision for mechanical fuel pump
• Reinforced deck surfaces for better sealing
• Foundation of our 502 engine assemblies

1Siamesed cylinder walls have thicker cylinder wall material with no water between the bores. This allows for a bigger bore; a bigger bore allows for more cubic inches and more power! 2Four-bolt mains have more material and more fasteners holding the crank in the block (4 bolts per main instead of just 2). Fourbolt mains help maintain the integrity of the block when you drop the hammer!

GM BOWTIE SPORTSMAN block

For the ultimate in sportsman drag racing or extreme street performance, GM Performance Parts has a full line of big-block block that feature full CNC-machining3, premium materials, and designs directly from GM. Our Sportsman block are available with tall decks4, one-piece or two-piece crankshaft seals5, splayed main caps6, and can easily be bored and stroked to 500+ cubic inches. Buy one of these block if you are a weekend drag racer looking to make 800 horsepower, or if you are building a serious street car with enough motor to crush the competition.

Bowtie Sportsman Block Technical Notes:
• Available in short deck (9.800") or tall deck (10.200")
• Requires Gen V - VI design one-piece rear main seal oil pans
• Machined for hydraulic roller and flat tappets
• CNC-machined to +/-.001" tolerance
• Nodular iron 4-bolt main caps, 16 splayed on center 3 mains
• Machined mechanical fuel pump pad
• Priority main oiling system
• Siamese Cylinder bores
• Gen V & VI style front timing cover required
• All bore finishes are ready to hone to size
• Clearance for 4.500" stroke
See chart on page 240 for complete specifications.

Standard Deck Sportsman block
25534363
Standard Deck Bowtie Sportsman Block
• 1-piece rear main seal
• CNC-machined cast iron 4 - bolt block
• 4.494" finished bore
• 4.600" max bore
• Tested to 800 horsepower!

25534362
Standard Deck Bowtie Sportsman Block
• 2-piece rear main seal
• CNC-machined cast iron 4 -bolt block
• 4.494" finished bore
• 4.600" max bore
• Tested to 800 horsepower!

3CNC or computer numerical controlled machining is an automated machining process that guarantees exact tolerances. No one offers as many CNC-machined block as GMPP! No one. 4Tall Deck block allow you to run a longer rod and/or a bigger stroke crankshaft for more cubic inches. More cubic inches means more power. Pump it up!

5A one-piece crankshaft seal is desirable to decrease the chance of oil leaks, but the two-piece seals allow for more aftermarket component attachments. You can retro-fit 2-piece seal block (built from 1965 to the present) for the one-piece seal.

6Our 16 splayed main caps have additional material holding the crankshaft in the block. GM Performance Parts uses splayed main caps throughout our entire line of performance-built big-block.

Tall Deck Sportsman block
25534364
Tall Deck Bowtie Sportsman Bare Block
• 1-piece rear main seal
• CNC-machined cast iron 4 -bolt block
• 4.494" finished bore
• 4.600" max bore
• Tested to 800 horsepower!

25534367
Tall Deck Bowtie Sportsman Bare Block
• 2-piece rear main seal
• CNC-machined cast iron 4 - bolt block
• 4.494" finished bore
• 4.600" max bore
• Tested to 800 horsepower!

25534368
Tall Deck 572 Bowtie Sportsman Bare Block
• 1-piece rear main seal
• CNC-machined cast iron 4-bolt block
• 4.560" fully honed bore
• 4.600" max bore
• Powdercoated Chevy orange
• (5) Windage tray bolts installed
• Tested to 800 horsepower!
• This is the block used for our 572 engines

GM ZL1 ALUMINUM BIG-BLOCK

The ZL1-optioned ’69 Corvette and Camaro were—without question—two of the most feared musclecars ever produced. The massive ZL1 427 aluminum big-block under the hood elevated these cars to instant classics the first day they hit the streets of America. Now, GM Performance Parts has re-introduced that same legendary aluminum block. It comes with state-of -the-art materials in our own flawless, blueprinted dimensions. Buy the ZL1 aluminum big-block, and you can build your own supercar!

See chart on page 240 for complete specifications.
ZL1 Aluminum Block Technical Notes:
• 356-T6M Aluminum block
• Steel 4-bolt main caps, 16 splayed on center 3 mains, dowel located
• Siamesed cylinder walls
• Centrifugally spun cast iron sleeves
• 4.240" finished bore
• 4.300" max bore
• 4.375" max stroke
• Standard deck height (9.800")
• Two-piece rear main seal
• Oil and water plugs are AN O-ring style
• Tested to 650 horsepower!

12370850
ZL1 Aluminum Big-Block
• 4.240" finished bore
• 4.300" max bore
• 4.375" max stroke
• Use sleeve P/N 12480035 (see page 249)

GM BOWTIE RACE block (CAST IRON)

These block are premium Bowtie big-block castings, designed for the engine builder who wants to machine their race block to their racing application. All of these block have thick deck surfaces, improved oiling, improved coolant flow, premium fasteners, premium 4-bolt steel splayed bearing caps—everything you need to start up a serious race program. If you want to build a 1200 horsepower big-block for your drag car, then buy one of these block and get to work. Hey, let’s go racing!

See chart on page 240 for complete specifications.
Bowtie Race Block Technical Notes:
• Available in short deck (9.800") or tall deck (10.200")
• Accepts Mark IV, Gen V–VI cylinder heads
• Use Gen V head gaskets with Mark IV and Gen V cylinder heads
• Use Gen VI head gaskets with Gen VI cylinder heads
• Blind tapped head bolt holes, extra inner head bolt bosses provided
• Requires Mark IV design two-piece rear main seal oil pans
• Requires Mark IV design crankshafts
• Can use Mark IV and Gen V-VI cams, timing sets, lifters and timing cover (Jesel belt drive cover may need machining for clearance)
• CNC-machined to +/-.001" tolerance
• 4-bolt SAE 8620 main caps, 16 splayed on center 3 mains
• Machined mechanical fuel pump pad
• Priority main oiling wet-sump system
• Provisions for dry sump oil line provided
• Honed cam and crankshaft bore
• Siamese Cylinder bores
• Improved cooling around No.1 cylinder
• .842" lifter bores, max 1.06", may be relocated
• Check distributor gear clearance at bottom of No.8 cylinder bore
• Each block supplied with sonic test data sheet

24502500
Standard Deck Bowtie Race Block
• CNC-machined cast iron 4-bolt block
• 4.240" finished bore
• 4.600" max bore (.250" min wall thickness)
• Standard deck height (9.800")
• Tested to 1200 horsepower!

24502502
Tall Deck Bowtie Race Block
• CNC-machined cast iron 4-bolt block
• 4.240" finished bore
• 4.600" max bore (.250 min wall thickness)
• Tall deck height (10.200")
• Tested to 1200 horsepower!

GM BIG-BLOCK DRCE (DRAG RACE COMPETITION ENGINE) block

Six-time NHRA Pro Stock world champion, Warren ‘The Professor’ Johnson, runs DRCE, why don’t you? This family of block was specifically designed for 500 cubic inch Pro Stock drag racing competition. The camshaft has been raised, the distributor hole has been moved, and the bore spacing allows for the preferable big bore with short-stroke pistons and crankshaft for enhanced performance. The big bore design unshrouds the heads so you can run bigger valves and get more air into the engine. Even the head bolt holes are not drilled, so either Pontiac S/D, Olds DRCE, or Chevrolet bolt pattern heads can be used. Our DRCE 3 block is the latest Pro Stock block that features a raised camshaft, lighter weight, and the latest evolution of Pro Stock design from some of the best racers in the world. All of these block are sold ‘solid’, without the lifter or head bolt holes drilled and tapped, which allows Pro Stock race teams to design their own specific locations for maximum power. Whatever it takes to make you a champion, GM Performance Parts is there!

See chart on page 240 for complete specifications.
RCE Block Technical Notes:
• CNC-machined to +/-.001" tolerance
• No. 2 & 4 main bearing bulkheads moved .060"
• Priority main oiling dry-sump system
• No lifter bosses, solid bar can be drilled as required
• No head bolt holes
• Siamese Cylinder bores, 4.900" bore spacing
• Bell housing bolt pattern accommodates Olds, Pontiac, & Chevy bolt patterns
• Each block supplied with sonic test data sheet
• Dual starter mounting locations
• Front engine mounts only
• Requires camshaft with distributor gear behind rear bearing
• Uses Big-Block Chevrolet crank, cam, balancer, flywheel and water pump

A. 24502572
DRCE 2 Bare Block, Gray Iron
• CNC-machined iron 4 -bolt block
• 9.525" deck height, may be machined to 9.000"
• Camshaft raised to 5.750"
• Cam tunnel accommodates 55mm cam bearings
• 4.500" semi-finished bore
• 4.700" max bore
• 4-bolt SAE 8620 main caps, 16 splayed on center 3 mains
• Oil pan rails spread .400" per side for additional stroke clearance
• Tested to 1400-plus horsepower!

12480026
DRCE 2 Bare Block, Compacted Graphite7
• CNC-machined compacted graphite 4 -bolt block
• 9.525" deck height, may be machined to 9.000"
• Camshaft raised to 5.750"
• Cam tunnel accommodates 55mm cam bearings
• 4.500" semi-finished bore
• 4.700" max bore
• 4-bolt SAE 8620 main caps, 16 splayed on center 3 mains
• Oil pan rails spread .400" per side for additional stroke clearance
• Tested to 1400-plus horsepower!

B. 25534403
DRCE 3 Bare Block, Gray Iron
• CNC-machined gray iron 4-bolt block
• 9.250" deck height, can be machined to 9.000"
• Camshaft raised to 7.067"
• Cam tunnel accommodates (9) 60mm cam bearings
• Cam tunnel is closed (no oil drain to rotating assembly)
• 4.590" semi-finished bore
• 4.700" max bore
• 2.500" crankshaft main journal
• 4-bolt SAE 4140 “doweled after assembly” main caps, 22 splayed on center 3 mains
• Highest available quality main studs
• Oil pan rails spread to 12"
• Oil and water plugs are AN O-ring style
• Tested to 1400-plus horsepower!

25534406
DRCE 3 Bare Block, Compacted Graphite7
• CNC-machined compacted graphite material 4-bolt block
• 9.250" deck height, can be machined to 9.000"
• Camshaft raised to 7.067"
• Cam tunnel accommodates (9) 60mm cam bearings
• Cam tunnel is closed (no oil drain to rotating assembly)
• 4.590" semi-finished bore
• 4.700" max bore
• 2.500" crankshaft main journal
• 4-bolt SAE 4140 ‘doweled after assembly’ main caps, 22 splayed on center 3 mains
• Highest available quality main studs
• Oil pan rails spread to 12"
• Oil and water plugs are AN O-ring style
• Tested to 1400-plus horsepower!

GM CYLINDER BLOCK COMPONENTS

A. 14015334
Four-Bolt Main Bearing Cap
• Heavy-duty iron four-bolt main cap is used on bearings #1, #2, #3 and #4
• Semi-finished cap must be machined to register the cap in the block
• Main bearing housings must be align-bored after installing new caps

B. 6264902
O-Ring Seal (Sold Individually)
• Use under the rear main bearing cap on all 1991-andnewer Gen V and Gen VI 454 and 502 engines

C. 10106460
Outer Main Cap Bolt, Gen V & Gen VI
• Used with Gen V and Gen VI (1991-and-newer) big-block with four-bolt mains
• Sold individually; order 10 per engine.

3859927
Outer Main Cap Bolt, Mark IV (not shown)
• Used with Mark IV (1965–1990) cast iron big-block with four-bolt mains
• Sold individually; order 10 per engine.

D. 10106461
Inner Main Cap Bolt, Gen V & VI
• Used with Gen V and Gen VI (1991-and-newer) big-block with four-bolt mains
• Sold individually; order 10 per engine.

3909834
Inner Main Cap Bolt, Mark IV (not shown)
• Used with Mark IV (1965–1990) cast iron big-block with four-bolt mains
• Sold individually; order 10 per engine.

E. 88962212
Main Bearings, 572 Engine
• Complete main bearing kit for 572 block with standard-size mains

F. 12495501
Freeze Plug & Oil Plug Kit
• Complete plug kit for new and rebuilt big-block engines
• Includes brass freeze plugs, cam bearing hole plug, oil galley plugs, water outlet plug, hex-head pipe plug, cylinder head and transmission dowel pins

3743389
Freeze Plug, steel (Mark IV) (not shown)
• Steel freeze plug for Mark IV (1965–1990) engines

3826963
Freeze Plug, brass (Mark IV) (not shown)
• Brass freeze plug for Mark IV (1965–1990) engines
• Suitable for marine applications

G. 88891749
Freeze Plug, Brass (Gen V & Gen VI)
• Brass freeze plug for Gen V and Gen VI (1991-and-newer) engines
• Suitable for marine applications

12480035
Cylinder Sleeve (Standard) (not shown)
• Steel cylinder sleeve for aluminum block P/N 12370850 only
• Sleeve has 4.240" bore and finish-bores to 4.250"

3902885
Windage Tray Stud (not shown)
• Used for mounting splash shield P/N 3967854

10224104
Windage Tray Stud, Gen V 454 & 502 (not shown)
• Used with Gen V 454 and 502 engines

H. 88958656
Windage Tray Bolt, 572
• Used with 572 engines

GM FRONT COVERS & TIMING POINTERS
I. 10230954
Timing Chain Cover, Gen V & VI
• Aluminum cover with timing indicator fits all 1996-andnewer Gen V & VI engines
• Currently used on 454 HO and 502 HO crate engines