- Engines & Components
- Engine Blocks
- Chevrolet Performance Big Block Chevy Bow Tie Sportsman Engine Blocks
For drag racing & extreme street machines, these blocks are cast from the best iron and CNC-machined (an automated process that ensures precision) to achieve maximum performance. They offer a standard or tall deck; tall decks allow cubic inches to be increased using a larger crankshaft. Bow Tie Sportsman Blocks can be bored and stroked to 500+ cubic inches, and they have 16° splayed main caps with extra material to secure the crankshaft. Blocks can be fitted with a 1-piece seal to reduce the risk of oil leaks or 2-piece seal to accommodate more components.
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Specifications
- Cast Iron Block
- CNC-machined to +/- .001'' tolerances
- Standard deck (9.800'') or tall deck (10.200'')
- Nodular iron 4-bolt main caps splayed 16° on the three center mains
- Clearance for 4.500'' stroke crankshaft
- Siamese cylinder bores
- Bore finishes are ready to hone to size
- Priority main oiling system
- Machined for mechanical fuel pump, hydraulic roller, and flat tappets
- Blocks with 1-piece rear main seal use the Gen VI-style 6-bolt front cover (#809-10230954) and Gen VI-style oil pan
- Blocks with 2-piece rear main seal use the Mark IV-style 10-bolt front cover and Mark IV-style oil pan
Standard Deck
Chevrolet Performance Bow Tie Sportsman Engine Block (1-Piece Rear Main Seal), Standard Deck
Chevrolet Performance Bow Tie Sportsman Engine Block (2-Piece Rear Main Seal), Standard Deck
Tall Deck
Chevrolet Performance Bow Tie Sportsman Engine Block (2-Piece Rear Main Seal), Tall Deck
The classic Chevy big block production engine was introduced in 1965. In the late 1980s, a new version arrived, designed for marine and fuel-injected applications. The early engines are known as Mark IV big blocks while later blocks are Gen V and Gen VI. You can tell them at a glance by checking for a mechanical fuel pump mounting pad. If it has one, it's aMark IV. If there's no fuel pump pad, it's a Gen V block. Despite the fuel pump mounting pad difference in their castings, the cylinder blocks of the Mark IV and Gen V are based on the same design. There are several other differences, particularly in the water jackets near the deck surfaces, that make some Mark IV and Gen V parts incompatible (e.g. cylinder head gaskets). Within the last few years, Chevrolet Performance revised the basic big block architecture to standardize the Mark IV and Gen V, creating an all-new cylinder block casting that combines the features of both generations. It also incorporatessignificant updates and strength-enhancing features that make the big block a stronger engine foundation with provisions to support 21st-century performance. Although the basic big block architecture is revised, Chevrolet Performance continues to offer two versions, each differentiated by performance and displacement capability. The Bow Tie Block continues to be the block of maximum performance, and Chevrolet Performance crate engines use the revised big block design. Here's what distinguishes the latest Chevrolet Performance Big Blocks from earlier castings: |