Joined: Nov 2016
If it's oil on the *outside* of the plugs, I'm thinking the valve covers are just leaking. If it's on the inside, then yes, your engine is burning oil. It can't get into the cylinders through the heads very easy unless your valve seals are shot, and hopefully your mechanic would've caught that. Otherwise it's probably a ring issue - which would cause compression problems.
But all that aside: in order of likeliness, overheating is 1) improper timing, 2) radiator/cooling fan/shroud/thermostat issues, 3) carburetor problems, or 4) block issues. The first one you'd best check is timing, because that one's free, and just takes a bit of work.
I smile a lot. It makes people wonder what I'm up to...