PARTS INTENDED FOR COMPETITION USE ONLY.
Click for more details.

PARTS INTENDED FOR COMPETITION USE ONLY.
Click for more details.

SMALL-BLOCK BOWTIE SPORTSMAN BLOCKS

12480174

350 BOWTIE SPORTSMAN BLOCK, 1-PIECE REAR MAIN SEAL

Chevrolet Performance Small-Block Bowtie Sportsman Engine Block 4-Bolt Splayed Main Caps View

Chevrolet Performance Small-Block Bowtie Sportsman Engine Block Top Front View

Chevrolet Performance Small-Block Bowtie Sportsman Engine Block 2-Piece Rear Main Seal View

Chevrolet Performance Small-Block Bowtie Sportsman Engine Block for use with 1-Piece Seal Adapter Bottom Rear View

CNC-machined cast-iron competition block
+/-0.001” machining tolerances
4-bolt mains, splayed caps on center three mains
3.980” finished bore

4.155” max bore (siamesed cylinder bores)
Extra-smooth gasket surfaces
Tall lifter bores
Comes with rear seal adapter

12480047

350 BOWTIE SPORTSMAN BLOCK, 2-PIECE REAR MAIN SEAL

Chevrolet Performance Small-Block 350 Bowtie Sportsman Engine Block with 2-Piece Rear Main Seal Bottom Rear View

Chevrolet Performance Small-Block 350 Bowtie Sportsman Engine Block with 2-Piece Rear Main Seal Rear Bottom View

Chevrolet Performance Small-Block 350 Bowtie Sportsman Engine Block Valley Top Front View

CNC-machined cast-iron competition block
+/-0.001” machining tolerances
4-bolt mains, splayed caps on center three mains
3.980” finished bore

4.155” max bore (siamesed cylinder bores)
Extra-smooth gasket surfaces
Tall lifter bores

12480175

350 MAIN, 400 BORE SIZE BOWTIE SPORTSMAN BLOCK, 1-PIECE REAR MAIN SEAL

CNC-machined cast-iron competition block
+/-0.001” machining tolerances
4-bolt mains, splayed caps on center three mains
4.117” finished bore

4.155” max bore (siamesed cylinder bores)
Extra-smooth gasket surfaces
Tall lifter bores
Comes with rear seal adapter

12480157

350 MAIN, 400 BORE SIZE BOWTIE SPORTSMAN BLOCK, 2-PIECE REAR MAIN SEAL

CNC-machined cast-iron competition block
+/-0.001” machining tolerances
4-bolt mains, splayed caps on center three mains
4.117” finished bore

4.155” max bore (siamesed cylinder bores)
Extra-smooth gasket surfaces
Tall lifter bores

12480049

400 MAIN, 350 BORE SIZE BOWTIE SPORTSMAN BLOCK, 2-PIECE REAR MAIN SEAL

CNC-machined cast-iron competition block
+/-0.001” machining tolerances
4-bolt mains, splayed caps on center three mains

3.980” finished bore
4.155” max bore (siamesed cylinder bores)
Extra-smooth gasket surfaces

Future GM Technicians Posing for a Picture with Dale Earnhardt Jr.

Bring Us Your Talent

Nobody knows automotive like Dale Earnhardt Jr. — so who better to share advice with aspiring auto techs?

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BLOCK-Module-Asset-MONSTER-CHEVELLE

The BLOCK

Visit TheBLOCK.com for a behind-the-scenes look at the world of Chevrolet Performance from an enthusiast's point of view.

Learn More

Four Chevrolet Camaro Sports Cars Parked on Display in a Showroom

Connect With Chevrolet Performance

Want to know the latest in Chevrolet Performance news and more? Connect with us via email and social media today.  

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Future GM Technicians Posing for a Picture with Dale Earnhardt Jr.

Bring Us Your Talent

Nobody knows automotive like Dale Earnhardt Jr. — so who better to share advice with aspiring auto techs?

View Technician Stories

BLOCK-Module-Asset-MONSTER-CHEVELLE

The BLOCK

Visit TheBLOCK.com for a behind-the-scenes look at the world of Chevrolet Performance from an enthusiast's point of view.

Learn More

Four Chevrolet Camaro Sports Cars Parked on Display in a Showroom

Connect With Chevrolet Performance

Want to know the latest in Chevrolet Performance news and more? Connect with us via email and social media today.  

Sign Up

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Unless specifically noted to the contrary herein, vehicles equipped with Chevrolet Performance parts that are emissions-related may not meet U.S., Canadian, and state and provincial laws and regulations relating to motor-vehicle emissions. These parts are designed and intended for use in vehicles operated exclusively for competition: in racing or organized competition on courses separate from public streets or highways. Visit www.chevroletperformance.com/emissions for more details.

Unless specifically noted to the contrary herein, vehicles equipped with Chevrolet Performance parts that are emissions-related may not meet U.S., Canadian, and state and provincial laws and regulations relating to motor-vehicle emissions. These parts are designed and intended for use in vehicles operated exclusively for competition: in racing or organized competition on courses separate from public streets or highways. Visit www.chevroletperformance.com/emissions for more details.