Exterior Components› Body Panels and Components

United Engine & Machine Co

PONTIAC 428 ROD 6.630 FLAT TOP +6CC 2V KB HYPER PISTON SET

$76.17

SKU: U00B KB304.040

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

Easy — 1–2 hours

Description

The Keith Black KB304-040 piston set is a set of 8 hypereutectic pistons designed for high-performance builds. These pistons feature a flat top with 2 valve reliefs and a 6cc volume. They are engineered with a low expansion 390 alloy and 16 percent silicon for tighter running clearances and improved oil control.

Key features include fully machined head and valve reliefs, triple spiral lock rings, and CNC machined pin bores for accuracy. The pistons also incorporate an accumulator groove for better ring seal, machined oil returns, and diamond-finished skirts with mini grooves to reduce scuffing. Wrist pins and spiral locks are included, but rings are sold separately.

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 KB304.040

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