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Gents,
Id like to pose a question and see what you guys think if possible, im from Australia and have a 6.0 with 235/243 camshaft, Ls3 cnc ported heads th400 with a 5500 stall converter and 4.11 diff gears and a very short runner intake from my measurements the runners are 3.5 inches long at best. The car makes 430whp at 7250rpm and a current best of 7.1 sec 1/8 mile 98mph and 11.0 124mph 1/4 mile with 1.6 60ft. My question is do you think and ls3 manifold would yield any better results at the drag strip? considering it should have a much better average power until at least 6000rpm.
Post more info on the whole car/combo. That intake is not doing you any favors with those heads/cam. Stock intake would be better for sure, but how much hood height do you have? Might consider a LSXRT, too.
[QUOTE=DualQuadDave;20585702]Post more info on the whole car/combo. That intake is not doing you any favors with those heads/cam. Stock intake would be better for sure, but how much hood height do you have? Might consider a LSXRT, too.[/QUOT
Thanks for the reply mate, the car weighs 3150 lbs when I race it with 235/60/15 et streets. The manifold is an original hand made sheetmetal from shauns custom alloy so I don't have the specs. I don't have the room for much of manifold an ls3 oem would fit and from my measurements one of those new summit efi low manifolds would possibly fit.
As DualQuadDave mentioned, this intake (or any other that looks remotely like it) is losing a lot of low and midrange power.
The LS3 stock intake would gain power with your setup. And you did say it would fit. I would switch back to it.
Post more info on the whole car/combo. That intake is not doing you any favors with those heads/cam. Stock intake would be better for sure, but how much hood height do you have? Might consider a LSXRT, too.[/QUOT
Thanks for the reply mate, the car weighs 3150 lbs when I race it with 235/60/15 et streets. The manifold is an original hand made sheetmetal from shauns custom alloy so I don't have the specs. I don't have the room for much of manifold an ls3 oem would fit and from my measurements one of those new summit efi low manifolds would possibly fit.
Yes, def go with a stocker. Call GPI, they have ported stock LS3 stock intakes ready to go. That is your best bang for the buck. That cam you have isn't great either, but one change at a time. I would crank up the compression, too. What is it at now?
Thanks alot, not sure on comp the heads are 0821 heads and from what I've heard they have had .30 thou taken off.
what size cam would be better? It's mainly a street/ strip combo. I'm actually considering going to 3.7 rear end to make it a little better on long drives.
The ls3 intake will make better overall power, but with a 5500 stall under WOT your gonna blow right passed any advantage the LS3 intake would give.
What RPM are you shifting at? Those short runner intakes generally pick up power passed 6500 over the stock LS3
From: Coast of San Mateo County Between Pacifica & HMB
My .02
FAST LS3 with BOTH Standard & Mid-Length Runners.
Standard for the street, Mids for the track.
Mids will work much better at the track given your stall & cam,
Standard much better on the street.
Easy quick swap.
We made 560rwhp with a stock LS3 intake manifold, stock L92 heads, BTR stage3 cam stroker cam (416ci was this size) on 91 octane 11:1 compression thru a T56 Magnum and 12 bolt rear running 335/30/18 tires.
Unless you are winding it out well past 7000rpm the LS3 intake is hard to beat.
Good point was made on the converter, that 5500rpm is way too much. I would get a quality 3700-4000rpm stall like a Circle D or PTC or Precision. If it's a street car, build it for the street and just enjoy. I would leave the cam alone for now, just swap the I take abd converter and keep working the combo.
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Intake manifold 
