GM Performance Parts
Big Block Chevy V8 Blocks
 

10134367 Gen V Tall Deck Pro Stock Bow Tie Bare Block (Production Line Machined) $1784

Same as P/N 10185049 except it has a deck height of 10.200". Casting P/N 10134366.

24502500 "Gen VI" CNC Machined short Deck Racing Bow Tie Pro Stock Block $2624

This bare block is the same as P/N 10185049 except it has all 8620 steel main caps and all are CNC machined with standard 9.80" deck. The Gen V CNC-machined race prepared short deck Bow Tie block starts with the same casting used in the P/N 10185049 production machined block. All of these blocks feature blind head and accessory mounting bolt holes, a deck configuration that enables the use of any big block Chevrolet cylinder head, and cylinder bores that may be bored to 4.600" diameter while maintaining a minimum wall thickness of .250". In addition, the new castings design improves engine block life and build ability of the previous generation of Mark IV big block Chevrolet blocks. CNC machined race prepared Bow Tie blocks differ from the production machined Gen V Bow Tie versions in certain areas. CNC race prepared blocks start from a raw casting and are not "conversions" and use a rear seal adapter to convert the Gen V production type one piece rear main seal to a Mark IV type two-piece seal that facilitates the use of a widely available Mark IV style crankshaft. In addition, 8620 steel bearing caps are put in all locations to further increase the integrity of the bottom end. The intermediate caps also feature 16 degree splayed outer bolts which anchor the caps into the strongest section of the block and prevent bearing cap movement under high loads. Bow Tie race prepared, as well as production Gen V blocks use priority main style oiling, in which the oil flows from the main gallery near the cam, oiling the cam via a small hole, and directly to the main journals. The main oil gallery on these blocks is relocated and enlarged to 9/16" diameter to allow increase oil flow through the block. The oil cooler provisions found on all Gen V production machined blocks is eliminated so that plugging of this boss is not required when preparing for a racing style oiling system. CNC race prepared Bow Tie blocks have inner head bolt bosses which allow better retention of cylinder heads in high horsepower applications due to cylinder head "lifting" from the block due to high cylinder pressures. The tall and short deck race prepared blocks weigh 288 and 278 pounds respectively which is at least 12 pounds lighter than imitation Bow Tie aftermarket blocks.

10185049 Gen V Short Deck Pro Stock Bow Tie Bare Block (Production Line Machined) $1784

The Gen V short deck Pro Stock Bow Tie bare block has been improved for the serious pro stock or boat racer. The Bow Tie block has siamesed cylinder walls, and a one-piece rear main oil seal. Some of the enhancements to the block are: extra thick deck surfaces with blind tapped head bolt holes, a relocated main oil gallery from the drivers side oil pan rail to the camshaft tunnel, mechanical fuel pump boss has been removed, and the block's front bulkhead moved forward to improve coolant flow around the No. 1 cylinder. This block also has machined main bearing bulkheads with four-bolt bearing caps. The Mark IV cylinder head can be used on this Gen V block.

10237292 Bare Block "502" $1510

This Gen VI cast iron block is a strong foundation for a big-block engine project. The "short-deck" block was designed to meet the needs of a powerful and dependable 500cid engine for street or boat usage. The block's cylinder walls are "siamesed" and are bored to 4.47". The deck surfaces are reinforced to improve the head gasket sealing. Four-bolt main bearing caps are installed to reinforce cylinder barrels and add strength to the bottom end.

Technical Notes: The distance from the crankshaft centerline to the deck surfaces is 9.80". It is used on 502 engines assembly, and partial engine. and can use roller tappet or standard tappet. Casting P/N 10237300. Maximum over bore is 4.500".

12370850 ZL1 Aluminum Big Block $5774

The Chevrolet ZL1 Aluminum Big Block is back and better than ever. This block was first introduced in the 1969 Corvette and Camaro. It was one of the rarest production engines ever built. Now the improved version is available. This block is based on the original tooling. The new casting is made from 356-T6M aluminum alloy and has a 4.250" cast iron liner that can be bored to 4.300". The bottom end has also been improved with new four-bolt splayed steel main caps, with dowel pins to locate and hold the caps in place. This block includes screw-in freeze plugs with o-ring seals, and a two-piece rear seal. The new block has a provision for both dry sump or regular oil pump systems and mechanical fuel pump. All GM performance cylinder heads will fit this block and it only weighs 110 lbs. The maximum stroke is 4.375".

12550307 Bare Block 427/454ci $1049

This is a special Gen VI bare iron block with 4.25" cylinder bores with four-bolt main bearing caps. It has a machined fuel pump pad, one-piece rear main seal design and standard 454 deck height.

Technical Notes: The maximum cylinder bore is 4.25" plus .060" O.S. and will require the "Gen V/GenVI" design one-piece oil pan. Casting P/N 12550313

14044808 Bow Tie Block (Tall Deck) $2099

This "CNC" "tall" version of the heavy-duty Mark IV Bow Tie block is recommended for maximum-effort racing engines with long-stroke crankshafts. This tall block has siamesed cylinder walls and reinforced decks with lower blind head bolt holes. It is equipped with four-bolt main bearing caps.

Technical Notes: This block has semi-finished 4.250" diameter cylinder bores. The distance from the crankshaft centerline to the deck surfaces is 10.20". It has provisions for a mechanical fuel pump. Casting P/N 14044807. Can be bored to 4.500".

24502502 Gen VI CNC Machined Tall Deck Racing Bow Tie Pro Stock Block $2624

This bare block is the same as P/N 24502500 except it has tall 10.200" deck height.

24502572 Bare Block - GMPP/DRCE "2" $3569

This GM performance parts/DRCE 2 Bare Block is a redesigned Old's DRCE. This block was designed for competition in 500ci Pro Stock Drag Racing or similar type usage. Use with cylinder heads P/N 24502585 or P/N 12480010 only. The main differences between the Old's DRCE and these semi-finished GMPP "2" blocks are the camshaft has raised to 5.750", the deck height is a 9.300" and can be reduced to approximately 9.000", the distributor hole is moved rearward on the block, and the overall weight has been reduced approximately 11 pounds. The cylinder bore centerline spacing has been increased from 4.840" to 4.900", the maximum legal bore spacing for NHRA Pro Stock competition. With the new bore spacing of 4.900" it will allow the use of big bore with short stroke piston and crank shaft combinations to enhance performance. The increase in cylinder bore spacing reduces valve shrouding and permits the use of larger valves to improve air flow. The semi finished cylinder is bored to 4.500" dia. maximum recommended bore dia is 4.700. New elliptical siamese cylinder barrels maximize wall thickness on the major and minor thrust axes. This allows lighter weight piston and rod combinations and improve carburetor, manifold port alignment with pro stock type induction systems. This block's cam tunnel will accommodate a 2.166" cam bearing. Other improvements are No. 2 and No. 4 main bearing bulkheads are relocated .060" to distribute crankshaft loads easily. The lifter bosses has been replaced with solid bar, and the lifter holes are not drilled to allow engine builders to position them for there own valve train geometry. The head bolt holes are not drilled, so the engine builder can accommodate Pontiac S/D, Oldsmobile DRCE, or Chevrolet bolt patterns. The rear flange has a hybrid patter that accommodates Oldsmobile, Pontiac, or Chevrolet bellhousing. They use new four-bolt 8620 steel main bearing caps with splayed outer bolts to improve main bearing bulkhead durability and resist bearing bore distortion under high load. The oil pan rails have been spread .400 per side to provide room for longer stroke crankshafts. The starter motor can be mounted on either side of the GMPP/DRCE Block.

Technical Notes: This high-strength iron block has brinell hardness of 210 to 230 and requires a camshaft with distributor gear behind the rear bearing. The balance of parts to complete this engine are Chevrolet Big Block (water pumps, crank, cam, balancers, flywheel, and manifolds). This block is cast with the GM Performance Parts logo on it.