A clean(internally) engine with ATF and stored in a plastic zip-lock is about "fail-safe". Don't make it any more complicated than that. I have a number of older engines given to me as part of an estate. Most are seized (locked with old gummy fuel) and will require bearings and gaskets in some cases. Really not sure if the cost is worth it? If I go thru them I will store them with ATF and in individual bags.........