What is the horsepower rating for this rotating assembly?

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

What materials are used in this rotating assembly?

The crankshaft and connecting rods are made from strong 4340 forged steel. The pistons are forged from 2618 aluminum, and the wrist pins are premium chrome moly.

Can this rotating assembly be shipped to California?

No, this part is not CARB approved and cannot be shipped to California due to emissions regulations.

Specifications

Brand: Manley Performance
Part #: 38555
UPC: 807298086538

Manley Rotating Assembly, BBC 555 4.250 STROKE/4.560/-3cc

Name: Manley Rotating Assembly, BBC 555 4.250 STROKE/4.560/-3cc
Brand: Manley Performance
SKU: manley-performance-manley-rotating-assembly-bbc-555-4-250-stroke-4-560-3cc-t14-881180
Price: 3777.80 USD
Availability: BackOrder

$3777.80

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Manley Rotating Assembly, BBC 555 4.250 STROKE/4.560/-3cc. 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 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 ARP 2000 cap screws are available for increased horsepower support.
2618 forged aluminum Platinum Series pistons are included.

This rotating assembly is designed for Big Block Chevrolet (BBC) engines. Check manufacturer specifications to confirm compatibility with your specific engine build.

⚠️ 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

Manley Performance is well-known for making strong internal engine components, and this BBC rotating assembly is a prime example of their commitment to robust parts. This kit is designed for big block Chevrolet engines and features a 4.250-inch stroke with a 4.560-inch bore, creating a 555 cubic inch displacement. It’s a complete package 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 durability 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, capable of handling up to 900 horsepower. If your build demands even more, you have the option to upgrade to ARP 2000 cap screws, which will support up to 1,500 horsepower. The pistons are forged from 2618 aluminum in Manley's Platinum Series, complete with premium chrome moly wrist pins for reliable operation.

This rotating assembly is a substantial upgrade for performance-oriented big block builds. Please note that this part is not CARB approved and cannot be shipped to California. Always refer to the manufacturer's installation instructions for proper assembly and tuning.