400 Main, 350 Bore Bowtie Sportsman Block

400 Main, 350 Bore Bowtie Sportsman Block

2-Piece Rear Main Seal

12480049 Chevrolet Cylinder Block

Step up to serious racing performance when you choose a Chevrolet Performance Block. These iron blocks provide a rock-solid foundation for any application in the 350-500-horsepower range, be it drag strip, circle track or high-performance project vehicle. These highly versatile blocks are available in a variety of finish options that enable maximum flexibility for building a wide range of engine combos. Most of the blocks have siamesed cylinder walls and 4-bolt main caps that are secured with Grade-8 bolts. Chevrolet Performance Bowtie Sportsman Blocks have 9.025-inch deck heights.

Bowtie Sportsman Block Technical Notes:

ﾕ Standard 9.025-inch deck height
ﾕ Nominal cylinder wall thickness is 0.340-inch
ﾕ Minimum cylinder wall bore thickness on 4.155-inch bore is 0.225-inches (excluding P/N 10051181, 10051183, and 10185047)
ﾕ Extra-thick deck surfaces have blind-tapped bolt holes for improved head gasket sealing
ﾕ Priority main oiling system
ﾕ Main bearing bulkheads are 0.900-inch thick and use Grade-8 bolts
ﾕ All five cam bearing locations require 2.000-inch O.D. (1.867-inch I.D.) bearings P/N 12370843 (except block P/N 10051183)
ﾕ Tall lifter bore blocks may require clearancing the top of the lifter bores for some roller lifters
ﾕ Lifter valley oil scavenging boss below bell housing flange is present, but not drilled and tapped
ﾕ Oil dipstick holes are not drilled
ﾕ Timing system clearance must be checked

Notes: Siamesed cylinder walls have thicker cylinder wall material with no water between the bores. This allows for a bigger bore; a bigger bore allows for more cubic inches and more power!

4-bolt mains have more material and more fasteners holding the crank in the block (4-bolts per main instead of just 2). 4-bolt mains help maintain the integrity of the block when you drop the hammer!