Roll over questions

Son rolled his tj the other day, just got it in a closed workarea last nite and started stipping the nose and windshield, interior. Started it up to back it in up a ramp and it smoked like a sob. We only ran for about a minute to get it in. I'm assuming the 45 min or so it was upside down that oil got in the cylinnders. It has been sitting upright for about 3 days. So my guess it the smoke is from the oil thats left in the cylinders and on top of the pistons plus whatever leaked into the intake runners. Engine runs smooth, no misses or anything. Any other issues to deal with when talking about a motor thats been upside down. Other than the wiped out nose, W/S, soft top, fan shroud and cage it looks OK. One local mentioned that he had heard of valves cracking when this happens, dunno about that.

chang th oil in it and run her till she clears out.May or may not have to change the Spark plugs.

Most of the damage, I´ve seen was from water, but imagine oil on the cylinder, could cause about the same problems.
Bent vavle, actually made the top of the valve a bit concave. looked funny, kind of like an inside out mushroom.
Cracked compression ring, noticed a slight fall in compression (in one cylinder) and what seemed to be a little more than normal blowby. Out of curiosity, I looked into the spark plug hole with a flashlight (and good mirror), with the piston near the bottom and saw a couple of scratches in the cylinder wall. Caught it early, only took a new set of rings, ridge ream and honing. If I would have let it go, it may have run, but probably not of lasted long.