Single 21253 Piston 9.75:1 1275 .060

Best performance stock pistons have a possible compression ratio of 10.0:1. Current pistons differ from the 60s originals, improved with a "low drag" slipper skirt design and a shorter lighter wrist pin. Wrist pin height is 1.5276", top dish is 8.4cc.
Performance is enhanced by the use of 3mm oil rings and the smaller drain slot behind this ring decreases the risk of breakage.
Sold Each.