Chevrolet Performance 12480049 - 400 Main, 350 Bore Size Bowtie Sportsman Block (2-Piece Rear Main Seal)

• CNC-machined cast-iron competition block • +/-.005" machining tolerances • 4-bolt nodular mains, splayed caps on center three mains • 3.980" finished bore • 4.155" max bore (siamesed cylinder bores) • Tall lifter bores