Head gasket getting oval?

I think I'm with moper on this one, swapping to a different head gasket may fix the symptom, and maybe permanently, but I don't think it's as simple as saying it's head gasket failure, case closed. I say this because I have installed Fel Pro gaskets on about a half dozen different engines of different makes and the only time I had a failure was when I didn't have the head resurfaced, and that could have been a cracked head. I never got back into that engine to see. If it were me I would mark some head bolts where the gasket would meet the head and make sure they easily thread into the block at least that far. If they don't thread easily chase the holes with a tap. Then have the wrench calibrated and bolt the heads down with new gaskets. Check fitment of the intake manifold to the heads and block. If the heads and block have been milled significantly the intake may need to be milled as well. Please don't take this the wrong way, I'm just trying not to take anything for granted, but did you follow the factory torque PATTERN?