Exterior Components› Body Panels and Components

United Engine & Machine Co

CHRYSLER HEMI 392 ROD 6.958 FLAT TOP +4CC 2V KB HYPER PISTON SET

$77.68

SKU: U00B KB289.040

Special Order
Special Order
Ships in 4–6 weeks
Free Shipping
Non-Returnable Item
INSTALL DIFFICULTY
DIY PRO SHOP

Professional / shop required

Description

The United Engine & Machine KB289.040 is a set of 8 pistons designed for performance applications. These pistons feature a flat top with two valve reliefs and are constructed from hypereutectic aluminum. They have a 4.040 in. bore and a 3.900 in. stroke, with a stock engine stroke type.

The pistons have a compression height of 1.940 in. and a piston head volume of +4.00cc. The wrist pin style is press-fit or floating, with a pin diameter of 0.984 in. The piston ring thickness is specified as 5/64 in. x 5/64 in. x 3/16 in.

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

BrandUnited Engine & Machine Co
Part NumberU00B KB289.040

Buy with Confidence

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