Speed Pro Cast Piston Standard H631CP offers the performance / dependability of O.E. pistons.FeaturesHigh Quality AluminumControlled Casting Machining for improved reliability, and durabilityUp-tilt ring grooves improve piston to ring sealing provide greater blow-by controlFitsPerformance, Chevrolet, Small Block, 350 Based Engines (4.000 Bore x 3.480 Stroke)