Engines and Components› Pistons and Piston Rings

United Engine & Machine Co

1 SET KB373.STD/1 SET 4000AM8.STD

$616.56

SKU: U00B KB373KTM.STD

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

Professional / shop required

Description

Keith Black Hypereutectic pistons are a great choice for high performance marine, drag race, circle track, street or towing application builds. The low expansion 390 alloy with 16 percent silicon allows for a tighter piston to wall running clearance. Fully machined head and valve reliefs, triple Spiral Lock Rings, and CNC machined pin bores ensure quality and performance. Wrist pins and spiral locks are included; rings are not.

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 KB373KTM.STD

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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.

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