This listing is for Set of 8 Speed Pro Hypereutectic Pistons compatible replacements for Ford 351W Windsor-series V-8 . Flat head w/4-valve reliefs. Coated skirt pistons. Good for street/strip and very limited race. 5/64" 5/64" 3/16" ring grooves. .912" pin diam. - pins included. Stock 5.956" length rods. Press or Float pin. Stock 3.500" stroke.