New Superior Cylinder - Grumman Style: Here we look at what is in the box of a new Superior Cylinder for a Lycoming O-360-A4M in the Last Yankee. Valves are lapped into the bosses in this new cylinder but you will have to set the ring gap in each cylinder. the 1260 written on the piston box is the gram weight of that piston. Video 1,578 in the Hit Parade. Join this channel to get access to perks: null