I am possibly thinking of going to the next step on my 06.

I want to be stealthy, dont want the dealer to know.

Anyone out there with experience replacing or RnR stock heads to increase compression and flow better along with a cam for better performance?

It would be nice to do this and keep it under the radar, so to speak to avoid any majr warranty issues and smog issues if I can.

Anyone?

 

Well, I'm not the expert, but I've been looking into this too and here's what I've come up with. (1) The cam will do a lot more good than the heads for a lot less money. (2) A fairly mild cam will give you most of the horsepower a fairly radical one will. (3) The heads are needed more with more cam, as (a) you'll need increased flow, and (b) you'll need more compression.

There is a formula for a "cam factor", (intake duration + exhaust duration) / 2 - 2 * lobe separation angle, with numbers in the range of -10 or below indicating a smooth idle, numbers around zero indicating a rough but livable idle, and numbers around +10 indicating something you probably wouldn't want to drive everyday.

So here are some cams that you might consider (intake / exhaust duration - intake / exhaust lift - lobe separation angle - "cam factor"):
Stock cam 207/217 - .525/.525 - 116.0 - -20.0
2002+ Z06 cam 204/218 - .550/.550 - 117.5 - -24.0
Lingenfelter GT2-3 207/220 - .571/.578 - 118.5 - 23.5
Comp Cams 212/218 - .522/.529 - 114.0 - -15.0
Comp Cams 216/220 - .525/.532 - 114.0 - -10.0
Comp Cams 212/218 - .558/.563 - 115.0 - -15.0
Thunder Cheatr 214/230 - .601/.578 - 117.0 - -12.0

The first two cams increase the lift with little change in duration and should be good for 20-30 HP. The middle two add duration more than lift and I'd guess would be good for 30-40 HP. The last two increase duration as well as lift and might add 30-50 HP. Of course your milage may vary

Increasing lift past .570 will require changing valve springs - not a big deal.

With any luck some of the cam swap experts like CAYVette will jump in here and help out.

 

First of all, the dealer will know, or can find out fairly easily. Usually they don't care much, so long as you don't bring the car in for warranty with a blown engine.

In order to maximize the benefit of the cam and/or heads, you will need to get a computer tune. Without it the engine may not idle well, and the air/fuel mixture may be off. The tune will change the check digit in the computer, and the dealer will be able to see it. Some tuners allow you the ability to reload the stock tune, others do not.

If you buy a set of heads off the shelf, many of the vendors stamp their logo right on the front of the heads for all to see. If you get a custom ported set, you will need to pull off your stock heads, ship them to the porting shop, wait for them to be ported, then re-install them.

Unless you get a mild cam, the car will idle differently. The previous post provided a common formula for computing valve overlap, which is what affects the idle. I had a 218/224 .550" 114 LSA cam in my '99 SS Camaro, and it idled great (after some tuning). Most folks could not tell that it had a cam in it just by listening to it. However, an experienced GM mechanic with good diagnostic tools could probably tell in a minute.

If you're going to get a heads & cam, you won't get the best performance at all with the OEM exhaust system. However, as soon as you bolt on headers, the dealer will know instantly.

Bottom line is that it's almost impossible to completely hide the fact that you have installed aftermarket mods to the engine. However, it's not that big of a deal. Maybe you just don't want a car that screams "MAJOR MODS" as soon as you fire it up, and that will pass emissions testing w/ no problems. If so, pick one of the cams previously mentioned, have it installed, enjoy your new-found power, don't worry about it further.

 

GM Performance parts make severl different LS6 and LS2 heads. They are stamped with the 243 casting numbers. So once installed they look just about the same.

You cam choice should be based on the heads you have or the heads you choose. Yes Heads and cam are a good idea.

Rember you do have to tune the car after the install.
and HITMAN99 is correct. a good technition will know the moment he plugs in the diagnotic compter that it is not stock.

 

Very helpful gentleman. Thank you

Currently I have the Calloway CAI, American racing long tubes, Corsa and I have had two dyno tunes thus far (one for each mod) and am putting out 380 rwhp.

I want to get to the 400 mark without sacraficing reliability and driveability.

Does Gm make an aftermarket cam for the C6? If I understand correctly, a cam from a c5 zo6 would provide a higher lift/duration and add poss 20hp?

 

Yes, the C5 Z06 (LS6 engine) went from 385 to 405 rated HP from 2001 to 2002, the major change was the cam. The LS2 uses the 2001 LS6 cam and the heads are essentially the same, so it would be reasonable to expect about 20HP gain from that swap. The main difference is more lift, from .525 to .550.

For that matter, going to 1.8:1 rocker arms should add at least that much HP without the pain of a cam swap. That would increase the effective lift of the stock cam to about .566 - I'd be quite careful about doing this with the stock valve springs, but it might work.

GM also offers the PN 12480033 "hot cam", at 219/228 .525/.525 112.0 it should make more power but won't idle like stock!

The LS1 and LS6 had a cam timing wheel at the back, the LS2 uses the cam gear for this, so an LS6 cam will have an extra wheel on it but that shouldn't cause a problem.

If you want all GM parts, there are GMPP heads:
88958765 LS2 CNC heads, 64.5 cc chambers
88958665 LS6 CNC heads, 65.0 cc chambers

These heads have 250 cc intake and 85 cc exhaust ports. The LS6 heads are more expensive, they have hollow-stem intake valves and sodium-filled exhaust valves. Both of these should make for a more durable valve train, especially with a hot cam but probably are overkill for the milder cams unless you spend a lot of time over 4000 RPM.

There's also a 88958622 LC6 CNC head with a 61.9 cc chamber, but you'd almost certainly need to go to at least the 219/228 cam to run those.

Check this thread regarding rocker arms: http://forums.corvetteforum.com/show....php?t=1456516

 

A few unorganized thoughts:

Do not use hollow stem valves. They are the reason I had to get a forged motor in my 2001. They are weak and one broke into 2 peices taking my whole motor with it.

The 1.8 rocker arms will net you near 20hp without the invasive cam swap.

Heads will gain you power even if you stay with the stock cam.

The stock cam isnt 207/217 as posted above, its 204/211.

The stock springs arent good to .570 lift as commonly talked about. They barely control .550@ 6000rpm.

Get dual valves to use with Crane 1.8's. The combo is silent and doesnt give any hint of a mod having been done. VETTEno2 has this combination and I was in the car. He also has the FAST manifold which was a very noticable difference.