are you running a stock headgasket or a low comp one? my friend mike bought the one advertised in an old import tuner mag where you could run upto 20psi on stock internals. we thought it was BS so he bought it since he had 2 engines cause of when he crashed his old car. so he put it in and he boosted it to 18psi with an RHI turbo or something like all i know is that snail was huge. that and the engine held for the 2 years that he drove it, then after 2 years he crashed again...lol