Thom

Well, there must be a reason why Corleone used massive torque on LARGE headstuds and a Phuzion headgasket...

DLS

How did you solved your problem Thom?

Tom M'Guinn

A stock HG and studs should be able to hold normal combustion pressures at 17.5psi all day long. Your cylinder pressure should be comfotably within range of the HG to seal at that boost level. As long as everything is ok mechanically (everything perfectly flat, no knicks, no cracks), I would focus your efforts on how the motor is tuned -- starting with less ignition timing around peak torque. A dyno with knock detection earphones would be a great investment too, but absent that try pulling out say 5 degrees on boost, and make sure you have your AFR correct for e85 if that's what you're running and that you are not maxing our your injectors or the like.

Also, as I said above, I've found that once you push coolant past a gasket, it seems to pave the path for the gasket to leak even if nothing is wrong. So, I would swap it out before trying to tackle the problem again.... (sorry)...

DLS

My engine is not so stock any more, lots of things is done with it.
My head is ported and very shaved and with e85 and high boost i don´t think the stock gasket and the old stock studs is up for the task.

Tom M'Guinn

I know opinions vary, but I've had pretty good luck with Raceware studs torqued up to 90- 100 ft lbs. Of course nothing can hold the pressure of high boost detonation. Might be worth a knock counter if nothing else.

Thom

I haven't run on E85 again and don't plan to.
A 3.0L at 18psi on Euro 98 is plenty fast already, well for me at least.