hi there cylinders huh!!!!!!!!!!!
it all depends on how badly they are damaged as they can be re-welded and repaired to standard form and early mc18 cylinders fit.i have been down this road before and they are becoming rather hard to come by.
piston kits are easy to get hold of and im sure that someone on the forum will point you in the right direction for cylinder repairs. if you get stuck i have one mc16 cylinder that needs repairing and replating spare as well as a pair of mc18 cylinders in the same condition.............
and welcome to the forum.