Product Description


This item is for eight (8) STANDARD bore Speed Pro (Sealed Power) hypereutectic flat top pistons with 2-valve reliefs and a cast piston ring set (Hastings/MAHLE) for Chevrolet 350ci (5.7L) small block V-8 engines. P/N (8) H631CP-STD + 139-STD.

If you're looking for pistons with an unbeatable combination of performance and value, then Speed-Pro hypereutectic pistons are for you. These pistons are manufactured from aluminum alloy that contains 16 percent silicon for greater strength and wear resistance. They're also molded in the latest permanent-mold technology to ensure the precise fit and tight bore clearances that today's top engine builders demand. Hypereutectic pistons are ideal for use in high performance street, bracket, and oval track racing—and will work perfectly with normal ring end gaps.


  • Bore: 4.000 in. (at standard bore)
  • Stroke: 3.480 in. (stock)
  • Connecting Rod Length: 5.700 in. (stock); rods NOT included
  • Piston Top Style: Flat top with 2-valve reliefs
  • Piston Head Volume: +5.00cc
  • Compression Height: 1.560 in.
  • Piston Material: Hypereutectic aluminum
  • Wrist Pin Diameter: .927 in.; pins included
  • Wrist Pin Style: Press-fit or floating; pin clips included
  • Ring Land Sizes: 5/64-5/64-3/16 (oil ring); rings included
  • Notes: DurOshield coated skirts
  • Usage: Street and mild strip; up to 75HP nitrous
  • RPM Range: Idle - 6,000
  • Compression Ratio (approximate): 10.5:1 w/58cc; 9.8:1 w/64cc; 8.7:1 w/76cc

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