I am strongly considering 1.85 rockers for a little better breathing (thanks to the generous input from the forum!!).. SO, now to the intake manifold! Z06 or Holley? Since I am trying to keep this smog legal for CA inspections, does anyone know if the Holley is legal as a replacment? ORRRR, is the stock C5 manifold good to go until a head change or other internal work? I only have 5,000 miles on this rig, so I am not tearing the motor apart until the warranty is up... Just bolt ons for now...

I have a 2003 m6, Z06 air box, KN filter, x-pipe, 3.42(soon to be 3.90's), and if I can ever find some used B&B shorty headers I'll add those too..(It never ends!!!)

I have not seen any intake manifold banter... Let's rock!

 

Your stock manifold is a Z06 so your fine on that. The aftermarket ones haven't proved their worth yet. :yesnod: :thumbs:

 

:iagree: There has been no proven huge gains on the aftermarket manifolds. At least not enough to justify the high price tags. Chris

 

The holley is the exact same as the LS6 manifold on the inside, its just aluminum for easier porting or nitrous :cheers:

 

Your stock manifold is great, I know because I changed from a LS1 intake to
the later style intake and they do work better. I would wait for more testing on the LSX. I'm not too sure if the LSX has a Carb number so it may not even be legal and it would never pass a visual inspection.

:flag

 

Stick with what you've got, definately. I had to pay $400 to get YOUR intake bolted on my car. :) Also consider - if you want to do cam later on (highly recommended if you like more power) many cams such as XE-R lobes or most high lift lobes will not be recommended for the 1.85 rockers due to very fast ramp rates and having too much cumulative lift (all depends on setup - springs, etc). At least that is what I've picked up around here.

 

:iagree:

 

:iagree:
And furthermore, the holley being aluminum will soak heat more efficiently than the composite LS6 manifold you already have. All 2001 and up LS1's have the LS6 manifold.
Also, if you are going that agressive with your rockers, you may consider higher lift springs. I also have to agree that if you put a more aggresive cam in you won't be able to use those expensive rockers. At $600 for rockers and springs and another $300-$400 for install, then another $300-$400 for a tune is a lot of money for maybe 10-12hp and most of it up top.
Since you have an M6 you would be better off putting a set of 4:10's in instead of 3:90's. 4:10's rock and they are smog legal. Also, maybe an aluminum flywheel. I've only got a couple of boltons and my car has gone from being spirited to sick with gears. :reddevil

 

If you get charged $300-400 for a rocker install you've either got more money than sense or ADD, The job should only take about an hour. Take off the coil packs, valve covers, rockers, install new rockers, button it up. It's easy horsepower but, as stated, it will limit future cam choices.

 

I was saying $300-$400 for rocker install and spring change. I agree that is a lot of money for just bolting on rockers. It should be less than half that for just bolting them on, and if you do it yourself it's free. It's been suggested that the more agressive, 1.85 ratio rockers should have new springs installed. I could see that the stock LS1 springs may start to float at top rpm's considering it happens with stock springs at slightly higher that 6k. :(

 

Seems to be some confusion on which manifold I have... I have an LS1 manifold, ie. stock... Do you think it is worhwhile to swap the LS6 manifold in place of the LS1 manifold? I do have the Z06 air box and high flow bridge.

 

Since 2001, the LS1 and LS6 engines have shared the same intake manifold.
You can call it the LS6 manifold if you wish, but it's the same one you already have on your car.

:cheers:

 

To clarify if your LS is 2001 or newer (including F-body) you have the same intake manifold as the LS6/Z06, you're good. I agree with those above that state the other intakes are probably not worth it.

As far as the rockers go, and limiting your cam upgrade size later, it will limit you on the bigger cams, because it increases your max lift. However if you decided to go with an agressive 232/237 cam, instead of buying someone's stock grind (ie. 232/237, 580/585, your increased lift modifier would make your lift 631/637) you could just order a custom grind from CompCams with a lower lift. Not sure what the min or max would be. You can always call comp-cams help line, check the website at http://www.compcams.com tell them you are considering their 1.85 rockers and ask all the questions you like for free :thumbs: Again, good luck...

I am going with their 220/224 530/534 cam which will compliment the 1.85 rockers nicely, giving me a net lift of 577/581 well within specs on the stock LS6 springs I have, or the comp 26918s.

Again, I also warn you that you may get charged some extra labor if the estimate did not take into account modifying the valve covers. I think I paid 2.5 hours labor total on the job, and may have gotten something else done with it, cant remember.

As far as the headers go, I wouldnt suggest wasting time or money on the shorties, go with some long tubes.

If you haven't already, you will definately need some kind of progam/editor to modify your pcm for the gear change, and with the rockers and your current setup, it probably wouldnt hurt either. If you don't feel like messing with it, take a drive to Long Island and let The Vette Doctors hook you up with the gears and tune/program, maybe a set of Long Tube headers. Absolute pro's, reasonable pricing, and a great track (no pun intended) record. (No I don't work for them, they work for me when I can afford it heh)


[Modified by IFLUBYU, 1:16 PM 2/1/2004]


[Modified by IFLUBYU, 1:24 PM 2/1/2004]


[Modified by IFLUBYU, 1:28 PM 2/1/2004]

 

You said you have a 2003 Vette, so you already have the LS6 intake. All base vettes in 2001 got the ls6 intake along with the ZO6.

I would just keep your ls6 intake because the holley heatsoaks and makes the same power as the ls6 unless you port it which raises the price even more. The LSX intake is a better buy than the Holley.


[Modified by Cobraeater, 12:19 PM 2/1/2004]

 

Which intake manifold for "bolt on" level C5?

The one it came with. Buying anything else at this point is a waste of money in my book.


[Modified by XTrooper, 1:36 PM 2/1/2004]

 

Thanks all for filling me in on the fact that I already have the Z06 intake!!! This forum has paid off many times for a vette rookie!

 

:iagree:

Same here! :thumbs: