Engines and Components› Pistons and Piston Rings

United Engine & Machine Co

1 SET KB375.STD/1 SET 4125BM8.STD

$551.70

SKU: U00B KB375KTM.STD

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Overview

The United Engine & Machine KB375KTM.STD is a piston and ring kit designed for Chevrolet Small Block V8 Gen I engines. This kit features pistons made from a strong Cast 390 Hypereutectic Alloy, heat-treated to T-6 standards. The pistons have a dome style with a hollow dome design and come with two valve reliefs, measuring -11cc in crown volume. This kit is designed for a 4.125 inch bore and a 3.750 inch stroke, suitable for engines like the Chevrolet 400 cubic inch (6.6L).

Each piston is lightweight for improved throttle response and RPM changes, while maintaining the strength needed for high compression and temperatures. The kit includes piston rings with a 1/16 in. x 1/16 in. x 3/16 in. configuration, featuring moly-coated cast iron top rings. The kit is sold as a set of 8 pistons with rings and wrist pins included. It is compatible with a wide range of applications from street and towing to marine and race. The year range for compatibility is listed as 1970-2018.
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1 SET KB375.STD/1 SET 4125BM8.STD

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.

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Specifications

BrandUnited Engine & Machine Co
Part NumberU00B KB375KTM.STD
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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.

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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.

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