by the time you get your cylinders sleeved and ported, you're gonna have too much money into them in my opinion. call some builders and ask around to see if they have some laying around. I bought a complete kit the other day (long rod crank, coolhead, domes, cylinders, and pistons for $500 just buy calling one and asking what he had laying around. The cub cylinders basically killed the pricing on stock cylinder setups, because everyone ditched them in favor of the cubs.
good luck