Piston Set of 4Fits GM 3.0L 181 Marine Dish TopSize = .020 OversizedBore Diameter (STD)AlloyTop Ring2nd RingOil RingPin DiameterCompression Height101.60mm (4.000in)Hypereutectic5/64in5/64in3/16in0.92741.625Need Rings? To check our inventory, please Click Here for Cast or Click Here for Moly