Usually when they get really hot they change shape. With 5 bolts around each hole, it's rare for a big block to really "pop" a gasket. But that doesnt mean they can't seap or leak after... I agree - that one pic shows clearly the coolant's coming from above the head flange. I dont think, unless the engine was rebuilt and it did it from day one, that the exh studs are a problem. I'd be much more concerned with heads cracking around the "shared" exhaust flange in the center of the head. Also, overheating can wound pistons, and almost always hurts the rings. So if it pegged the gage, and it's leaking, it may be worth your while to pull it and inspect things anyway.
