New Competition Series pistons for Sportsman big-block Chevrolet racing engines

• Forged, inboard piston bodies for lightest weight and maximum strength
• Vertical gas ports for maximum ring seal
• H13 piston pins for maximum reliability

Clinton Township, MI: Diamond has announced a new line of pistons for the highly popular big-block Chevrolet Sportsman racing engines.

26dDiamondBBC-CompSeriesKnown as their Competition Series, they are suitable for most 24- or 26-degree valve angle big-block cylinder heads. As expected, they cater to race engines in several favored classes, including Top Dragster, Top Sportsman, ET Bracket, which encompass all popular 500 and 600-plus cu in big-block engine packages.

Diamond’s new Competition Series pistons are created from the more shock-resistant 2618 aluminum alloy inboard forgings. In addition, they are lighter in weight than the conventional piston body, yet their inboard-style structure provides greater strength and as such accepts small to medium applications of nitrous.

Equally appealing are their vertical gas ports. Visible around the perimeter of the piston’s top deck, they transfer combustion pressures to the inner edges of the top rings deftly sealing them to the cylinder walls. To reduce friction in the cylinder bores and combat wear, a molybdenum coating is applied to the piston skirts as standard.

With familiar big-block Chevrolet deck heights of 9.800in and 10.200in., the compression ratios are configured with the piston set at 0.005in to 0.020in below the deck surface. Bore sizes from 4.500in to 4.625in are accommodated as well as compression ratios from 14:1 to 16:1. Compression heights range from 1.065in to 1.270in.

More interesting news is that Diamond’s Competition Series pistons are delivered with H13 tool steel piston pins (both Detroit-made) with wall thickness of 0.185in. The pins operate in robust pin bores equipped with twin oiling ports.

Inlet and exhaust valve relief depths are stated as 0.325in and 0.120in respectively and the pistons are configured to accept valves sizes of up to 2.350in and 1.900in. The top ring is placed 0.290in to 0.300in down from the crown. Lastly, Total Seal AP piston ring packages are offered as an option. Their dimensions are 0.043in x 0.043in x 3/16in.

Diamond’s Competition Series pistons will be available starting January 02, 2014.

For more information contact:
Diamond Pistons 23003 Diamond Drive, Clinton Township, MI 48035

Telephone (877) 552-2112 or visit or e-mail Mike Panetta at