Forged dished piston with valve reliefs. Must be used with LSX rods. Lightweight, includes rings and wrist pins. 4.185" bore, .866" wrist pin size. 1.2mm compression ring lands and a 2.0mm oil control ring land. NOTE: Not compatible with production-style LS connecting rods. Must be used only with new LSX connecting rods with 0.866" wrist pin bores.