My friend recently let another friend ride his 1982 ATC250R in the local dunes. Well that other friend fried the recently installed top end in about an hour (friend had throttle pinned entire ride). Well that recent rebuild was that sleeve's last bore because it had the largest piston made for that cylinder (.080 over). Now in need of a new sleeve I gave him the idea that a 350 Oddessy top end might mate to the bottom end of his R (they did it with a Pilot and TRX 250R).

Does anybody have any idea's about my idea of this swap? Is it even possible? Has anybody tried it before? If it is possible what should I look for to make it concrete proof that it is possible without having to buy parts first?