Aerorich,
I can identify with your interest in engines. I've always enjoyed working with them. I started working on automotive engines after a GM dealer ripped me off on a tune up. I figured I could mess it up cheaper than they could.
My interest carried over when I got back into aeromodeling. I still have a Saito .45 that I rebuilt into a new crankcase, after a crash cracked the original. That was "way back when" repair parts weren't ruinously expensive.
I have one of the original GMS .47's, the one with the large shaft nut. Picked it up used but it hauls a Tower Kaos around quite well. I found the nut and a washer at a local hardware store! Like you, I haven't needed engine parts in the normal running of things. Crashes and/or thrown props are another matter.
I noticed that a contributor to this thread mentioned needing parts for a ST .60. I have one that runs well but has a cracked muffler screw-boss. I'd sell it......
CR