Head gasket and bolt issues, my guess as well. Just like he said, when the head is lifting, you are pushing combustion into the water jackets and some of that air is traveling up to the thermostat causing it to close. When your car blows the gasket completely, your car will overheat no matter what. Try this- Turn your heater on full hot and boost the car up til you see the temps rise. Is the hot air coming out of the heater still hot when the temps are rising like that while you are under boost? If the air is cold, then you know coolant has stopped circulating and then you need to replace the head bolts with ARP fasteners and replace the head gasket. Have the head checked for warpage as well.