This a used set of JE forged pistons PN 258233 for big block Chevy. They fit a 4.500 bore with 1/16-1/16-3/16 ring grooves and are made from 2618 premium material. Oil ring supports are included. Compression height is 1.245, with a 42 CC dome and will fit 2.300 x 1.900 valves. Used less than 100 runs and are in perfect condition with no skirt or pin bore damage. They come with a new set of JE chrome moly pins (150gm). Also available with a used set of Precision Products taper wall 9310 material pins (136gm) or a new set of Manley tool steel pins (122gm) for an additional 100.00. Free shipping to you door in the lower 48 states when paying asking price!!