...
P.S i run a stock gasket on a poorly tuned 13psi runing 110,000km old un-surfaced block with arp studs and its still holding after almost 20,000 km of abuse!
I can concur if needed in regards about the engine anyway
Sounds like you have BHG, I had one 1 year ago with your symtoms and got the gasket replaced though mine was a stock gasket for my 5M-E, and now I have BHG between 2 cylinders (5M-E again )...