You will hear a pronounced ‘klackity-klack", especially at idle.

The ugly one of my three had only about 68psi of compression before I started running it. I have not measured it since then but it’s a great runner. If you’ve got the clunk, you may end up going through the powerhead, or just looking for a replacement. At 40 bucks, you’re still in pretty good shape on the investment if you ask me. If it were mine I would at least start it and see what it sounds like. If it’s clattering, pull the cylinder head and check for cylinder damage. If the cylinders are still good tear it down and replace the pistons, wristpins, and rebush the rods if they need it.
-Ben

Buc,
I understand everything you are saying. I try not to spend more than they are worth to fix them up too, but if it’s a keeper for my collection I don’t worry about it as much. As far as "collection direction," mine is largely classic OMC with 1950s-60s being the largest concentration. I do enjoy the antiques also so my collection direction is sort of all over the place, so I certainly get that. Those are great motors but if you decide you don’t want to deal with it, bring it with you to Tomahawk and I’ll give you the 40 bucks and haul it home with me. 😉
-Ben