how much boost can stock headgaskets take?

[sL103]

since i did a very nice build up on a 300ZX this summer we opted not to go with a copper gasket because according to a well known source the stock head gasket could take 29lbs of boost before blowing, Does anyone know what the rb25det would take before it belows i know it has a lower compression than that of a 300ZX tt respectively at 9:1:1 i know the rb20det is at 8:1:1 is that right?? and is the rb25det at 8:5:1?? has anyone used an aftermarket headgasket like HKS/NISMO/or Power Industries??
just checking with the guys that have done the rb25det swap

thank you, Shawn

[lbcklik1486]

The rb has 9:1 also.

[uiuc240]

Originally posted by James
Please only someone with an RB25 reply, don't speculate.

yeah, and there are SO many people here with RB25s...let alone ones with TONS of boost.

The SR stock head gasket is good for a lot of boost. It's a metal gasket. I'm sure the RB is the same. Avoiding detonation, I'm sure the RB would be good for 30-40 psi without popping. But you'll probably lift head bolts and hole pistons way before that.

Eric

[DuffMan]

Well Apex-i makes metal headgaskets for RB engines so I would try calling or emailing them, they should know. They do a lot of RB work. Also motorex could probably tell you, though i dont know if they do a lot of work on 25's.

[sL103]

i apperciate it