72 corvette heads, manifold, and camshaft questions
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Re: 72 corvette heads, manifold, and camshaft questions
If I was to use a flat top piston with a 70+ CC head, would it be down on power verses the 65 CC head and dished piston? More detonation prone on 93 octane fuel? I am probably going to get an assortment of dual plane manifold and try them on the dyno. Thinking a performer, performer rpm q jet, and a weiand or china version.
Re: 72 corvette heads, manifold, and camshaft questions
How much overlap is too much for a street motor like this. is 60 degrees too much? How much lobe intensity{is this a real term?} is too much or when does the valve train get noisy? Right now I am looking at a Howards cam ground with their fast ramp hydraulic roller with 269 degrees at .006 and 219 degrees at .050 it has .350 lobe lift so .525 with a 1.5 rocker. I am going to try a 106 LSA and install it on a 102 ICL. Flame away.
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jeff swisher
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Re: 72 corvette heads, manifold, and camshaft questions
For my testing the smallest chamber was always less detonation prone if everything else stayed the same on the head basically mill to achieve smaller chamber and test.
This was 54cc vs 64cc.
If the flow is not hurt with the 65cc chamber then I would do that with dish unless you already have flat tops.
I built 1 388" for a relative and milled the heads to 72cc and ran 214-224 @ .050 on a 112 LSA flat tappet.
Really strong power no detonation issues ran 91 octane 38 total timing 3940 lb ElCamino 3.08 gear.
Your 106 lsa should close the intake valve much earlier than that above generic grind and make even more low end grunt.
That ElCamino could get air under the driver front tire at the track.
Those heads were 624 castings I ported and left the 1.94-1.50 valves in them.
Flat tops with 5.5 cc reliefs. compression was right about 9.8 and 10.5 would have not bothered me a bit.
But it was a build whatcha got on hand deal.
As far as noisy cam a lot of that is in the lifter or the preload you put on it and the ramps on the cam.
You could have a cam with same duration and less lift and if the ramps are not gentle closing it can be noisy.
So just looking at lift and duration will not tell you what the thing will sound like.
I care less what the valvtrain sounds like as long as it is not beating it's self up.
I have had noisy hydraulic flat tappets and some very quiet solid flat tappets.
This was 54cc vs 64cc.
If the flow is not hurt with the 65cc chamber then I would do that with dish unless you already have flat tops.
I built 1 388" for a relative and milled the heads to 72cc and ran 214-224 @ .050 on a 112 LSA flat tappet.
Really strong power no detonation issues ran 91 octane 38 total timing 3940 lb ElCamino 3.08 gear.
Your 106 lsa should close the intake valve much earlier than that above generic grind and make even more low end grunt.
That ElCamino could get air under the driver front tire at the track.
Those heads were 624 castings I ported and left the 1.94-1.50 valves in them.
Flat tops with 5.5 cc reliefs. compression was right about 9.8 and 10.5 would have not bothered me a bit.
But it was a build whatcha got on hand deal.
As far as noisy cam a lot of that is in the lifter or the preload you put on it and the ramps on the cam.
You could have a cam with same duration and less lift and if the ramps are not gentle closing it can be noisy.
So just looking at lift and duration will not tell you what the thing will sound like.
I care less what the valvtrain sounds like as long as it is not beating it's self up.
I have had noisy hydraulic flat tappets and some very quiet solid flat tappets.