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Chevrolet Performance ZL1 Aluminum Engine Blocks 12370850

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Engine Block, Aluminum, 4-Bolt Mains, 4.240 in. Diameter Bore, 2-Piece Rear Main Seal, Chevy, 427, Each

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  • Order this item and get free delivery and handling on your entire order! Truck freight fees also waived on this item. Valid on orders shipped in the contiguous United States.

Brand: Chevrolet Performance

Manufacturer's Part Number: 12370850

Part Type: Engines, Bare Blocks

Product Line: Chevrolet Performance ZL1 Aluminum Engine Blocks

Summit Racing Part Number: NAL-12370850

Main Journal Type: OEM

Engine Block Style: Aftermarket

Deck Height (in): 9.800 in.

Cylinder Bore as Shipped: 4.240 in.

Cylinder Bore Diameter: 4.250 in.

Engine Block Material: Aluminum

Main Bolt Style: 4-bolt

Main Caps Included: Yes

Main Cap Material: Steel

Main Cap Fasteners Included: Yes

Main Bearings Included: No

Rear Main Seal Style: 2-piece

Finished Cylinder Bores: Yes

Raised Cam Location: No

Cam Bearings Included: No

Freeze Plugs Included: Yes

Quantity: Sold individually.

In-Store Pickup: Choose In-store pick-up (OH, GA, NV) on our web site.

Tool Stroker Combinations

These Chevrolet Performance ZL1 aluminum engine blocks feature an improved design of one of the rarest production engines ever built--the ZL1 aluminum big block used in 1969 Camaros and Corvettes. They feature a new casting made from 356-T6M aluminum alloy and have a 4.240 in. cast iron liner that can be bored to 4.300 in. The engine blocks allow for crankshafts with a maximum stroke of 4.375 in. and held in by 4-bolt splayed steel main caps.

Other highlights include:

* Thread-in freeze plugs with O-ring seal
* 2-piece rear main seal
* Provisions for wet or dry sump oiling systems
* Provision for mechanical fuel pumps
* Compatible with all types of cylinder heads


Some parts are not legal for sale or use in California on any pollution-controlled motor vehicles

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