What is the horsepower rating for this rotating assembly?

With the standard ARP 8740 cap screws, this assembly is rated for up to 900 horsepower. If you upgrade to the optional ARP 2000 cap screws, the rating increases to 1,500 horsepower.

What materials are used in this Manley rotating assembly?

The crankshaft and connecting rods are made from 4340 forged steel. The pistons are 2618 forged aluminum from Manley's Platinum Series, and they include Premium Chrome Moly wrist pins.

Are there any restrictions on shipping this part?

Yes, this assembly is not CARB approved and cannot be shipped to California due to emissions regulations.

Specifications

Brand: Manley Performance
Part #: 29555RHXX
UPC: 807298087443

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

Name: Manley Rotating Assembly, BBC 555 4.250 STROKE/4.560/+43cc
Brand: Manley Performance
SKU: manley-performance-manley-rotating-assembly-bbc-555-4-250-stroke-4-560-43cc-t14-880926
Price: 4211.70 USD
Availability: BackOrder

$4211.70

On Backorder

Order now to reserve yours — we'll ship as soon as stock arrives. Full refund if we're unable to fulfill.

Manley Rotating Assembly, BBC 555 4.250 STROKE/4.560/+43cc. Built for high-horsepower BBC builds.

Key Features

Fits Big Block Chevrolet (BBC) engines.
Features a 4.250-inch stroke and 4.560-inch bore with +43cc piston dish for 555 cubic inches.
Includes a 4340 forged steel crankshaft for strength.
Comes with 4340 forged steel H-beam connecting rods with 7/16" ARP 8740 cap screws.
Optional upgrade to ARP 2000 cap screws for increased horsepower capacity.
2618 forged aluminum Platinum Series pistons with Premium Chrome Moly wrist pins.

This rotating assembly is designed for Big Block Chevrolet (BBC) engines with a 4.250" stroke and 4.560" bore. It is not CARB approved and cannot ship to California.

⚠️ CA WARNING: This product can expose you to chemicals known to the State of California to cause cancer and/or birth defects or other reproductive harm. Learn more

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About this part

Product Details

If you're building a big block Chevrolet (BBC) engine and need a solid foundation, this Manley rotating assembly is a well-built option. It's designed for a 555 cubic inch displacement with a 4.250-inch stroke and a 4.560-inch bore, featuring a +43cc piston dish. This assembly is a critical component for anyone looking to build a serious performance engine.

At the heart of this assembly is a 4340 forged steel crankshaft, chosen for its strength and reliability under 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, but you have the option to upgrade to ARP 2000 cap screws for even greater strength. The pistons are forged aluminum from Manley's Platinum Series, featuring Premium Chrome Moly wrist pins. This combination of materials and construction is intended to handle significant power.

With the standard ARP 8740 bolts, this assembly is rated for up to 900 horsepower. If you opt for the ARP 2000 cap screws, that rating increases to an impressive 1,500 horsepower. Keep in mind that this assembly is not CARB approved and cannot be shipped to California. It's a serious piece for serious engine builds where durability and high performance are key.