I got a running, but wornout 350 and I have the case with crank, but not gas tank, off a 346. I also have a decent 346xp, 44.3 bore cyl, but no piston. It is my thinking that the 350 could benefit from just a new ring, simple easy fix. For not much more work plus a new piston, I can use the 350parts, to just build a 346xp. I think the gas tank, carb and all the covers will direct bolt to a 346 case. I have a 346 case gasket and even have a new 346xp decal for the starter cover. Or I could just put the 346 cyl on the 350. What would you do.