Engines and Components› Pistons and Piston Rings

Speed-Pro

Hypereutectic Pistons Set, 4.000" Bore, 1.560" Compression Distance

$322.99

SKU: H631CP

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Overview

The Speed-Pro H631CP is a set of 8 hypereutectic pistons designed for street performance, brackets, and oval track racing. These pistons are constructed from an exclusive FM244 high silicon alloy and feature Duroshield anti-friction coated skirts.

They are weight-matched sets and are manufactured in advanced piston facilities. The pistons have a flat top style with two valve reliefs, a 4.000" cylinder bore, and a 1.560" compression distance. They are designed for use with a 3.480" crankshaft stroke and a 5.700" connecting rod (350ci).
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The Speed-Pro H631CP pistons are engineered for demanding applications such as street performance, bracket racing, and oval track "claimers." They are manufactured from an exclusive FM244 high silicon alloy, providing enhanced strength and wear resistance. These pistons are further enhanced with sophisticated design and feature Duroshield anti-friction coated skirts. Each set contains 8 weight-matched pistons, designed and manufactured in advanced facilities. They are built to work perfectly with normal ring gaps and include wrist pins. The piston specifications include a flat top style with 2 valve reliefs, a 4.000" cylinder bore, and a 1.560" compression distance. They are designed for a 3.480" crankshaft stroke and a 5.700" connecting rod, resulting in a 350ci displacement. Compression ratio will vary based on cylinder head volume: 10.28" with 58.0 cc heads, 9.99" with 60.5 cc heads, 9.61" with 64.0 cc heads, 9.21" with 68.0 cc heads, 8.85" with 72.0 cc heads, and 8.52" with 76.0 cc heads. The ring groove sizes are 5/64", 5/64", and 3/16". Note that piston rings are not included, and these pistons are sold without warranty or guarantee of any kind.

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

BrandSpeed-Pro
Part NumberH631CP
CategoryEngines and Components
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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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