CYLINDER BLOCK AND COVERS Serial No. 7M1 to 7M222 Inclusive. NOTE: 4H7074 Piston and Liner Group, 2H5096 Cylinder Liner and Piston Replacement Gasket Group and 2H5086 Valve Grinding Gasket Group are Available. Piston and Liner Replacement Require the Use of 2H5096 and 2H5086 Gasket Groups