Manley Rotating Assembly, BBC 555 4.250 STROKE/4.560/+43cc

Manley Performance has a solid reputation for making tough engine parts that can handle serious abuse. This BBC 555 rotating assembly is a prime example, built for big-block Chevrolet engines that demand a lot of power. It’s designed around a 4.250-inch stroke, which is a key factor in achieving the displacement and torque you’re looking for in a performance build.

At the heart of this assembly is a 4340 forged steel crankshaft, chosen for its strength and ability to withstand high stress. Paired with it are 4340 forged steel H-beam connecting rods. These rods come standard with 7/16-inch ARP 8740 cap screws, a well-known name in high-strength fasteners, but you can opt for ARP 2000 cap screws for even more security. The pistons are forged aluminum from Manley's Platinum Series, complete with Premium Chrome Moly wrist pins. This combination of materials and construction means the assembly is built to last and perform under pressure.

This rotating assembly is rated for up to 900 horsepower when using the standard ARP 8740 cap screws, and it can handle an impressive 1,500 horsepower if you upgrade to the optional ARP 2000 cap screws. Keep in mind that this part is not CARB approved and cannot be shipped to California. It’s a serious piece of kit for a serious engine build.