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Hey everyone. I'm looking for some information. I am curious what people are doing for their head? I would like to build a head capable of revving to 8500rpm safely. I hope to have 2860-5s and poncams. Would it really be necessary to build the head? What do you recommend?
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1991 Nissan Skyline R32 GT-R: 710whp 521 ft/lbs 27.5psi 11.8 @126mph low boost -
quick answer... valve springs.
long answer.
old saying, "build the head for power and build the bottom end for strength"
I'm assuming you want = or < 600hp because you stated -5.
stock head with "drop-in" cams, cam pulleys and valve springs can make that power. and do it below 8000rpm.
if your head is worn out, there's no shame in rebuilding it to stock specs.
if you're doing competition or really feel the need for head work.
most important and effective modifications include port, bowl, and combustion chamber. more aggressive cams are also needed to see the benefits. something around 10mm lift is pretty good. this requires machining the head for high lift cam clearance. some companies make cams with smaller base circle for a no machining install. but those cams require aftermaket tappets ($$). stock tappet are fine so it's cheaper just to buy normal high lift cams and machine the head while it's being rebuilt. alots of research and/or a pro head builder with experience in RB's is required to balance the work. you don't want to have huge ports with small cams or vice versa.Comment
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here's another one OP:
i'm local and right in the middle of building my head. pm me if you'd like to discuss.oh hai!Comment
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this might help...
valve spring test:
Poncam:
Reimax street:
Group A cams:
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