What is the horsepower limit for this rotating assembly?

With the standard 7/16" 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 assembly can handle up to 1,500 horsepower.

What specific engine dimensions does this assembly fit?

This rotating assembly is designed for a 555 cubic inch displacement, featuring a 4.250 inch stroke and a 4.560 inch bore. The pistons have a +43cc dish.

Are there any restrictions on shipping this product?

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

Specifications

Brand: Manley Performance
Part #: 39555
UPC: 807298086798

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-t14-880987
Price: 4039.22 USD
Availability: BackOrder

$4039.22

On Backorder

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

Manley BBC 555 Rotating Assembly, 4.250" Stroke. Handles up to 1500 HP for serious builds.

Key Features

Fits Big Block Chevrolet (BBC) engines.
4.250 inch stroke with a 4.560 inch bore and +43cc piston dish.
Includes a 4340 forged steel crankshaft for strength.
Features 4340 forged steel H-beam connecting rods.
Connecting rods come with 7/16" ARP 8740 cap screws, supporting up to 900 HP.
Optional ARP 2000 cap screws are available for up to 1,500 HP.

This rotating assembly is designed for Big Block Chevrolet (BBC) engines. It is not CARB approved and cannot be shipped 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 serious big block Chevrolet engine, a strong rotating assembly is the heart of the operation. This Manley Performance rotating assembly is built for power, designed to handle the demands of high-performance street or race applications. It includes a 4340 forged steel crankshaft, 4340 forged steel H-beam connecting rods, and 2618 forged aluminum pistons, all engineered to work together as a balanced unit.

The crankshaft and connecting rods are forged from 4340 steel, a material known for its strength and durability under extreme stress. The H-beam rods come standard with 7/16" ARP 8740 cap screws, capable of supporting up to 900 horsepower. For those pushing the limits, an upgrade to optional ARP 2000 cap screws is available, allowing this assembly to handle an impressive 1,500 horsepower. The included 2618 forged aluminum pistons are part of Manley's Platinum Series, featuring premium chrome moly wrist pins for added reliability.

This assembly is designed for a 555 cubic inch displacement with a 4.250" stroke and a 4.560" bore, featuring a +43cc piston dish. Please note that this assembly is not CARB approved and cannot be shipped to California. It's a well-built foundation for a powerful engine build.