[Shane@DBPerformance]

Yea, sounds like a somewhat blown headgasket. You can have a barely blown headgasket that only shows itself under boost. I usually doesn't hurt power either, but can cause overheating and eventually fail in a much worse way.

Overheating can warped a head and blow a headgasket, but who knows which came first. Often overheating is caused by a blown headgasket. You might be able to just get the head decked and put in a stock headgasket. It is obviously easier to get the head decked than to pull the block and disassemble it to get it decked.

I had a problem with the 6-bolt motor that I got for my wife's 1G a few years ago. It could run or idle forever and never overheat, but as soon as you tried to do a boosted pull, it will push coolant like crazy. After trying everything and headgaskets, we had to pull the motor and get it decked. It hasn't had any problems with pushing any coolant since then.