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PARTS INTENDED FOR COMPETITION USE ONLY.
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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
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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?

Technician Stories

Technician Stories
BLOCK-Module-Asset-BFTT-alt

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

Learn More
Four Chevrolet Camaro Sports Cars Parked on Display in a Showroom

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

Sign Up

Learn More
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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.