....Even thought about a conversion to electric and packing the batteries in the nose.
But these days a motor and pack that has about the same power as an engine is only the same weight or LIGHTER.
If it's not covered yet and if the wood in the tail surfaces is built from "lead balsa" that would barely float it might be worth re-doing them from much lighter wood. Everything you save at the tail reflects at the nose 4 to 8 times over for a total saving of major proportions.
I would not worry too much about the engine. Shy of a crash the only stuff that will fail over time will be the bearings. And those are easily replaced with non OS parts. Use it and enjoy it. That's what it was made for. Or would you rather wait and die only to let some collector have it for pennys on the dollar? Live a little, enjoy your engine.