I dont know if this is going to find anything. IMO you've probably got a crack between a waterjacket and the exhaust crossover passages, you need need to feed pressure with the #3 or #5 exhaust valve open somehow. Not sure how you'd really do that. I think you need to pressurize the coolant system.
Now I need to pin those needles, got to feel that heat Hear my motor screamin while I'm tearin up the street
