Sale

Engines and Components› Pistons and Piston Rings

Eagle Specialty Products

Forged Rotating Assembly

$2,735.99 $2,590.99 Save $145.00

SKU: EAG12504040

In Stock
In Stock
Ships by Sep 9
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Advanced — 4+ hours

Overview

The Eagle Specialty Products 12504040 is an engine rotating kit designed for performance applications. This kit includes a forged 4340 steel crankshaft and forged aluminum pistons with a -4.00cc dome volume. It also features forged 4340 steel H-beam connecting rods with a 6.000-inch length.

The pistons are .040 inches oversized and utilize a floating wrist pin style. The kit is compatible with a 2-piece rear main seal.
Show original supplier description
The Eagle Specialty Products 12504040 is a competition-grade engine rotating assembly kit engineered for enhanced performance. This comprehensive kit features a robust forged 4340 steel crankshaft with a 3.750-inch stroke and a 4.165-inch bore, designed to replace OE components and support higher performance outputs. The assembly includes forged aluminum pistons with a flat-top design and two valve reliefs, featuring a -4.00cc piston head volume. These pistons are .040 inches oversized and utilize a floating wrist pin for durability. Complementing the pistons are forged 4340 steel H-beam connecting rods, measuring 6.000 inches center-to-center, known for their strength and reliability under demanding conditions. The rotating assembly is sold as a kit and includes rod and main bearings, but does not include a harmonic balancer, flexplate, flywheel, camshaft, lifters, or gaskets, requiring these components to be sourced separately for a complete engine build.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

Fitment Guaranteed

Don’t gamble
on fit.

Log your build in the MOTORMIA app and we’ll guarantee this part fits your exact setup — or your money back, return shipping covered.

Available on iOS & Android

Specifications

BrandEagle Specialty Products
Part NumberEAG12504040
CategoryEngines and Components

We’re here — turning wrenches, just like you.

Call us, follow along, or come say hi.

(760) 282-4645 Instagram Google

Buy with Confidence

Returns & Fitment

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

View Full Return Policy

Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

Free shipping over $200 in the continental US. Alaska, Hawaii, U.S. territories (Puerto Rico, U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands), and international orders carry surcharges — most appear at checkout. Some exceptions (LTL freight, or suppliers who quote freight only after we place the order) won’t. In those cases we’ll reach out with the exact charge before your order moves forward.

View Full Shipping Policy