I hate to be that guy, but it could be a slipped liner pressurizing your system. If you cooked it and popped the headgaskets, that is not an uncommon outcome. I second what was said previously, check for exhaust gasses.
That's not the problem. If it's anything internal, it will simply be corrosion.
That all may well be irrelevant, because by the time I manage to get this fucking squid hose on, I'll have to buy another hose kit.
I can't bend like this right now. I'm one more headache away from an engine swap just to be finished with it and have mine on a stand to polish back up, even if it's perfectly fine.
I have no time for this bullshit. I'm losing money every minute I'm out there, and losing even more with the bad mood after.