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intense stage 3 cam

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whitcomb

New member
i have some questions, facts, and contridicting things lol.. first im lookin into the intense stage 3 cam, the first thing i wanna know is are bigger valves nessecary or will stock be sufficient, i do have well ported heads so that will help.. 2nd is i should be able to get away with using LS6 springs, but i would like more opinions and the reason i say "should" is that the LS6 cam is a .550 lift cam. now for the contridicting, intense site says for lobe lift its .338/.344 @ 1.6 = .540/.554 , well if you figure out it actually comes out to be .540/.550, and thats at 1.6 now in 99 or 00 i think they switch to 1.66 rockers on the L67 so that woulld be .561/.571 @1.66 ratio, so technically i could run those ls6 springs and be safe with a 1.6 rocker, but i have a 2001 so that puts me over, and some may think that ls6 spring wont work yes there 90lbs but thats whne the valve is closed when open there only 5lbs less then a 130 open.. i just want some more opinions, on all this info....thanx
 


I'm subscribing, because I've been looking into these cams as well and am VERY curious.

I would think however, that if you don't used better heads, it just won't perform to it's full potential...but I'm still doing my study work.
 
General rule of thumb when installing an after market cam.

The cam should always match the heads.

I have the IS3 cam and run their S3 heads as well.

If your trying to run this cam with stock heads, and only changing the springs, your so not going to get your moneys worth out of that set up. With a cam that large you will need for sure, some extensive work done to your heads to allow that cam thumping to make your engine breath.

I run 1.7 adjustable roller rockers on my set up. Maxing out the 130# springs. Between the 1.6 and 1.7 you would be looking at around a 10-11hp difference.

If you don't want to get into switching the heads, then get a VS or a XP cam, and change out the springs on your stock heads at least. Thats my recommendation.

~F~
 
well i stated that there was porting done, my heads and intake are at DART gettin ported right now and a 5 angle valve job so that should help out..the only thing im not doin that the stage 3 heads have are over sized valves.....
 
With larger valves done right, you will notice a lot on the top end for sure. At the end of the 1/4 you will most likely have so much more power left you wish the track was a full mile so you can use it. It just flows that good.

~F~
 


When Intense dropped off a pair of stock heads, they told them, make these flow as much as you can. Stage 3 heads were born. There is so much machining to the intake runners, they actually started getting into the injector bosses. Many say, ZZP mostly, that this is bad. But if you match your LIM to the heads as I have done, there is no edge from LIM to Head, its as smooooooooth as glass. No lip what so ever.

~F~
 
I'd give them the specks of a stock cam, and what the heads are, and then give them the specks of the S3 cam, and they should be able to match them together.

~F~
 
well theve already done heads for a L67 before and from what i know they work with comp cam on everything , i told them what i have and they said they have all the info they need so well see how it turns out..
 
From what I've read...the biggest factor maker in improving the heads, is installing bigger valves, the bowl porting, and opening up the exhaust ports. On forced induction, the air is gonna find it's way whether the intake runners are opened up or not, and I think that I also read that opening up and smoothing the intake side can actually hurt performance. Gasket matching not counted in that....you want as smooth of a transition as possible where the two meet. Dave and I have a few discussions on this.

I don't think your Dart porting will be in vain though, they make good heads for a N/A application, so I imagine it's equally as good for the forced induction market.
 


dont forget to relieve the bores/CC to unshroud the valves...bigger valves just mean more valve shrouding in our small bores...

i have IS3 cam and heads for the whippledRiv and one IS3 cam for the 442 we are making our own heads with a welded chamber (peanut shaped) and maximum quench.

the IS3 heads have a huge intake port requiring porting be done to the alum carrier LIM gaskets

now if only we had an LIM with a better "highport" port design
 
The LS6 springs will work fine with the lift values of an IS3 cam, 1.6 or 1.66 rockers and stock valves.

The only issue with IS3 lift on stock heads is the geometry of the rocker at full lift. If they insert bronze guides, I'd consider running a roller rocker, otherwise your guides will get quite the workout.

When upgrading valves and not going through the effort to go to longer valves (LS1/Vortec), stock valves keep things simple and perform quite well.
 
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