What is the horsepower rating for this rotating assembly?

With the standard 7/16-inch ARP 8740 cap screws on the connecting rods, this assembly is rated for up to 900 horsepower. If you opt for the ARP 2000 cap screws, the rating increases to 1,500 horsepower.

What material are the crankshaft and connecting rods made from?

Both the crankshaft and the H-beam connecting rods are constructed from strong 4340 forged steel, chosen for its durability and ability to withstand high stress.

Are the pistons included with this assembly?

Yes, this rotating assembly includes 2618 forged aluminum Platinum Series pistons, which come with Premium Chrome Moly wrist pins for added durability.

Specifications

Brand: Manley Performance
Part #: 38555RHXX
UPC: 807298086606

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-t14-881187
Price: 4029.96 USD
Availability: BackOrder

$4029.96

On Backorder

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

Manley Performance BBC 555 rotating assembly. 4.250" stroke, 4340 forged crank and rods, 2618 forged pistons. Handles up to 1500 HP with ARP 2000 bolts. Part# 38555RHXX.

Key Features

Fits BBC (Big Block Chevrolet) engines.
Features a 4.250 inch stroke crankshaft.
Includes 4340 forged steel H-beam connecting rods.
Connecting rods come with 7/16 inch ARP 8740 cap screws, supporting up to 900 horsepower.
Optional ARP 2000 cap screws are available for connecting rods, supporting up to 1,500 horsepower.
2618 forged aluminum Platinum Series pistons are included.

This rotating assembly is designed for BBC (Big Block Chevrolet) engines. Please verify compatibility with your specific engine build and bore size.

⚠️ 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, reliable engine components, and this BBC rotating assembly is a prime example of that commitment. If you're building a serious big-block Chevrolet engine, this 555 cubic inch assembly is designed to handle significant power. It features a 4.250-inch stroke crankshaft, a 4.560-inch bore size, and a -3cc piston dish, making it a robust foundation for a high-performance build.

The heart of this assembly is the 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. For those pushing the limits, there's an option to upgrade to ARP 2000 cap screws, which raises the horsepower ceiling to a formidable 1,500 HP.

The pistons are Manley's Platinum Series, made from 2618 forged aluminum for a good balance of strength and light weight. They include Premium Chrome Moly wrist pins, which are known for their durability. This assembly is a well-built package for serious engine builders looking for a solid rotating assembly that can be trusted for demanding applications. Please note that this assembly is not CARB approved and cannot be shipped to California.