What is the horsepower rating for this rotating assembly?

With the standard ARP 8740 cap screws, this assembly is rated for 900 horsepower. If you opt for the upgrade to ARP 2000 cap screws, it can support up to 1,500 horsepower.

What are the key components included in this Manley rotating assembly?

This assembly includes a 4340 forged steel crankshaft, 4340 forged steel H-beam connecting rods with ARP 8740 bolts, and 2618 forged aluminum Platinum Series pistons with premium chrome moly wrist pins.

Can this rotating assembly be used in California?

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

Specifications

Brand: Manley Performance
Part #: 39555RH
UPC: 807298086842

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-t14-880992
Price: 4262.81 USD
Availability: BackOrder

$4262.81

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 up to 1500 HP.

Key Features

This rotating assembly includes a 4340 forged steel crankshaft.
It features 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.
The assembly comes with 2618 forged aluminum Platinum Series pistons.
Premium chrome moly wrist pins are included with the pistons.
This assembly is rated for 900 horsepower with the standard ARP 8740 bolts.

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

If you're building a serious big-block Chevrolet engine and need a foundation that can handle serious power, a Manley rotating assembly is a smart way to go. This 555 cubic inch assembly is designed for those looking to push the limits, whether for drag racing, serious street performance, or other demanding applications. It includes a robust crankshaft, strong connecting rods, and durable pistons, all engineered to work together as a balanced unit for your high-performance build.

At the heart of this assembly is a 4340 forged steel crankshaft, chosen for its strength and reliability under extreme stress. Paired with this are 4340 forged steel H-beam connecting rods. These rods come standard with 7/16? ARP 8740 cap screws, a well-known performer in high-horsepower engines. For those aiming for the absolute maximum, there's an option to upgrade to ARP 2000 cap screws, which allows this assembly to support up to 1,500 horsepower. The pistons are 2618 forged aluminum Platinum Series, known for their durability and heat resistance, and they come with premium chrome moly wrist pins for added strength.

This assembly is rated for 900 horsepower with the standard ARP 8740 bolts, and can be upgraded to handle up to 1,500 horsepower with ARP 2000 bolts. Please note that this assembly is not CARB approved and cannot be shipped to California. It's a substantial piece for a serious engine build, providing a solid core for your project.