i blew my old motor so i picked up a new one(not brand new) and put it in and it was smoking bad. so i took it back out and put all new internals in it including rings. i put everything back together with new gaskets and it is STILL smoking bad. the smoke is blue so its def. oil
Id bet its either bad valve stem seals on the heads or worn valve guides (or a combination of both). Or you might not have staggered the ring gaps so oil is still entering the combustion chamber. Id say thoise are the most likely culprits.