Hey guys, is the deck on GT40p heads to thin to use on a turbo setup? I just blew my second set of 9333's on the compression side and was told i really need alum heads because these are lifting under boost.. Could this cause the gaskets to blow? Both sets lasted about a year each and blew on the compression side both times.

 

The gt40p's are notorious for thin decks, and flexing that causes hg issues. A good aftermarket head is the answer.

 

Thanks.. That's what I was told by a couple others as well

 

Head studs are a must with P's if you're not already, a good safe tune and no more than 10-12psi should help. Theres guys making them work but yes, alums are the way to go. Multiple benefits.

 

I do use studs and I'm only at 10psi my tune is really good to. I have recently learned that the decks are just thin and not a good choice for boost.

 

How much timing? Timing reduced at MBT? 10-12 psi is safe for the P's with studs. Also make sure your surface finish is good on the deck and heads.

 

What is the max torque with studs and 9333's on these heads? Should they be torqued a little more since it's forced induction?

 

There are quite a few threads on this subject... Problem is not clamping force of fasteners, but the decks flexing between them. Some even say stock bolts hold better than studs. Some have run 16psi, and others have failures at 10psi... conservative timing at peak torque, and some luck will keep them alive above 10 psi for awhile.

 

FWIW I hit 20psi on more then one occasion with my gt40p's with reused stock head bolts.