He says issues in one cylinder, but around the plug area, looks like it was welded?

Agrred and I wouldn't run em

Dang, the cylinder looks Like it’s going to need a few hundred bucks to fix it. Unless you did your own machine work, would be better off with a new set.

It was just “detonation”.

If weld was ok, would have some promise. But should have welded up some of the chamber cuts. I’d be afraid of smoothing those down and loosing the cc’s in that chamber.

They do have a valve job. Some nefarious flipper will buy them and stick them on a “compete rebuilt motor” on Facebook from a private party. Unsuspecting buyer.