273 copper head gaskets SCE

UPDATE UPDATE ! I put on approx couple hundred hard miles since I installed the mr gasket1112 head gaskets and had the head milled so they were flat . Now I have another issue... It is huffing smoke/ exhaust pressure out the valve cover filler holes. both sides . Just happened so will do compression check on it today . either that head gasket pupped again or broke a ring or hole in piston. this is the 3rd time with issues. it's a 273 commando engine. I very seldom ever had to mat it to the floor and open the secondaries but the every time I gave a quick stab to the floor is when I always popped a head gasket. and now this issue. what is going on ?