Exterior Components› Body Panels and Components

United Engine & Machine Co

CHRYSLER 450 ROD 6.358 STEP HEAD 4.4CC 2V KB HYPER PISTON SET

$73.08

SKU: U00B KB251.030

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Professional / shop required

Description

The United Engine & Machine Co. KB251.030 is a set of eight hypereutectic pistons designed for BB Chrysler 450 applications. These pistons feature a flat top with two valve reliefs and a 4.4cc volume. They are constructed from a low expansion 390 alloy with 16 percent silicon, allowing for tighter piston-to-wall running clearance.

The pistons have a bore size of 4.372 inches, a crankshaft stroke of 3.750 inches, and a rod length of 6.358 inches. The compression height is 1.722 inches, and the wrist pin size is 1.094 inches. They are compatible with piston ring sizes of 5/64 x 5/64 x 3/16. The OE deck height is 9.980 inches.

Fitment

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Specifications

BrandUnited Engine & Machine Co
Part NumberU00B KB251.030

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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.

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