Eagle B12302L040 Competition Rotating Assembly Small Block Chevy Bore - 350 4.040

The Eagle B12302L040 is a factory-balanced competition rotating assembly designed for small block Chevrolet 350 engines with a 4.040-inch bore. This competition-grade kit is engineered to support engine builds up to 750 horsepower, with the potential to exceed 900 horsepower with upgraded rod bolts.

Complete Assembly Includes:

• Eagle 4340 forged steel crankshaft with 3.480-inch stroke for 1-piece rear main seal applications (1986-1999)
• Eagle forged 4340 steel H-beam connecting rods, 5.700-inch length with 7/16-inch ARP 8740 cap screw rod bolts
• Icon 4032 forged flat-top pistons (-3.7cc) with performance ring set
• H Series race rod and main bearings included

Compression Ratios: 10.8:1 with 58cc chambers, 10.1:1 with 64cc chambers, 8.9:1 with 76cc chambers. The "B" prefix in the part number indicates this assembly is factory-balanced and ready to install, eliminating the need for additional balancing work. The forged 4340 steel crankshaft features .125-inch fillet radiuses for superior strength, nitrided surface, and micropolished finish.

This premium rotating assembly delivers exceptional reliability and durability for high-performance street, strip, and competition applications. Internal balance design—flexplate/flywheel and harmonic balancer not included.