1990JEEPXJ,
Could you elaborate on your statement,"I already tried the gumout on the rings to no avail". Sometimes, with a piston with rings stuck-closed and on the bench, you have to flood the rings with Gumout carb cleaner and wait a couple of minutes before the rings snap-out.
Also, a broken ring or broken piston land ,between the piston-ring grooves, will produce massive oil blow-by. It appears, you may have to pull the pistons and look them over carefully. Typically, massive oil blow-by occurs when the piston rings are stuck closed or broken. So when the engine is running, the connecting rods' "oil squirter holes" are spraying oil on the cylinder walls for lubrication. The combustion pressure then blows the oil on the cylinder walls past the stuck-closed rings and/or any broken rings into the crankcase. The crankcase becomes pressurized, which in turn, pressurizes the valve-cover, which in-turn, blows excessive oil into the emission tubing, etc.
Good luck on your tear-down!
Best regards,
CJR