Thanks MJM460. I was able to fumble through to get this size. What was interesting with the 4032 piston, is that the lead screw impressions did not become visible up until the piston was lapped. The end result was a piston/liner fit that was 2-3 times wider than usual and would pump a lot more fuel. Also, when the battery connector was touched to the glow plug, the engine would "pop" and try to start without moving the piston.