VINCE

iTrader: (1)

Ok.. From what I have seen. There is not that much of a difference. I have seen both heads dyno over 440rwhp on a 346ci H/C setup. Yes in theory the LS6 heads should be better, but I have not seen definitive proof. Yes it should be more flow, but the best tuners are getting equal flow out of LS1 heads. Also, we have learned that high cfm does not mean high output or awesome #'s at the TRACK.. Why pay 1200 for LS6 heads when you can get LS1 or 6.0L heads for less than 450 bucks. Yes we have a few examples of LS6 heads doing well on the bigger engines, but what about the 346ci..? I think the LS1 heads on the bigger engines were doing just fine. Many have dyno'd over 500rwhp with LS1 heads.. This thread is to help those who have not made a decision on which heads to choose.. I personally think it is more the Head Porter than the heads themselves.. Yes a particular head might make the job easier for the porter, but is it worth the extra money to the consumer..?

JS

iTrader: (4)

Every point u made is correct but I think there worth about 8 to 10 RWHP over a LS1 head on a 346.

Most of the bigger engines really benifit from the LS6 heads and I figured if I ever step up to the plate I'll already have them...

JS

VINCE

iTrader: (1)

That is true JS the LS6 heads should be worth about 10rwhp more. Bigger engines seem to benefit well from it. I also think that it depends on the porter.. I was just looking at a set of GTP Stage 3 heads forsale. Flow #'s were crazy. By .600 lift the heads flowed something like 316cfm. Yes, the port work would cost you more, but if you figure in the price of the LS6 cores.. I think it would even out..

Jay 95WS6

what you have to do is compare the performance vs the price. if the LS6 core is more than the LS1 by 900.00 but you need to invest 1100.00 in machining work to equal the flow and compression then they are a good deal with the LS6's but if you don't want to spend that much money then LS1's are better for your application. conversely what about comparing LS6's to C5R's since we're comparing apples to oranges <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Jay

DrkPhx

iTrader: (15)

The GM CNC LS6 heads sell for $1800.00 which are ported by LPE. That's a good deal for an assembled unit (with the 2002 LS6 valves). Take in consideration they are ported for use with a relatively low lift cam in the .525-.550 range, and will increase compression also. With all of benefits, these have to be the best deal on heads out there. I have been holding off on heads for awhile and will go these when I get the $$$.

VINCE

iTrader: (1)

Yes the GM LS6 CNC heads by LPE are awesome.. I totally agree.. For the ones that do not buy these heads from the factory the cores cost 1200. Plus 2500 plus for Stage 2 heads on top of that. That equates to 3700 minimum. Stage 3 heads for LS1 go for a little over 3k depending on the vendor. LS1 heads you can get for 450 and less. Not to mention the fact the Stage 3 heads are going to most likely flow better than the LS6 Stage 2 heads. Granite Stage 3's are for bigger engines, but will work on a 346ci with the right cam combo. I could be wrong on all of this. I am just going by what some have told me they paid and from what I read on the boards.. The C5R heads are a whole different animal. PLus, I was told they do not even fit on a 346ci w/out some modifications done...

EuG

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Many have dyno'd over 500rwhp with LS1 heads.. </font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Who?

VINCE

iTrader: (1)

You are going to make me go back thru post? You can start with the first built 422ci's and ARE first built 427ci's..

EuG

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">You are going to make me go back thru post? You can start with the first built 422ci's and ARE first built 427ci's..</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I’m not sure what you mean <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

I think I know pretty much every big inch setup ever-posted on CorvetteForum or here (ls1.com a while back)

All the 500rwHP+ NA motors I can think of (hyd. cammed at least) definitely had LS6 heads and off-road setup. That’s why I’m curious if somebody had 500+rwHP NA motor with LS1 heads what are the details of the setup?
Maybe there’re some cool tricks I don’t know about <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> I’d like to learn!

I think on a big motor Ls6 heads are worth 10-15rwHP at least over Ls1 heads and it ain’t easy to break 500rwHP even with LS6 heads….

Richard@WCCH

iTrader: (3)

Since both types of heads are breathing through the same intake manifold, don't expect to see much gain. A 346cid engine making 440rwhp is producing 1.27hp per cubic inch. A nice 427cid makes 520 rwhp and works out to 1.21hp per cubic inch. The trend of larger engines making less hp per cu/in N/A prevails. Small engines will make peak power at higher rpms than large displacement engines given the same induction and exhaust systems. Hope this make a little sense. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

Cheers,
Richard <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

Bout'ItZ28

iTrader: (19)

[QUOTE]Originally posted by headbam:
Since both types of heads are breathing through the same intake manifold, don't expect to see much gain. [QUOTE]

exactly the ls6 intake flows the same no matter what heads u have on the car ~260-270cfm.

<small>[ August 04, 2002, 02:18 AM: Message edited by: Bout'ItZ28 ]</small>

VINCE

iTrader: (1)

Finally someone mentioned it.. The limiting factor.. The ls6 intake.. Thanks for bringing it up Richard..

VINCE

iTrader: (1)

Finally had a chance to do a search on this board, but not on ls1.com yet.. I found 9 guys on this board sporting 400 plus cubes. Most have changed their sigs or do not post horsepower #'s.. I think 3 are sporting LS1 Stage 3's and the rest LS6 heads.. Most did not put in their sig what heads they were running.. I guess the big money people are most likely sporting LS6 heads. So I could be wrong on the 500rwhp plus LS1 head guys. Also, when they first put out the big motors... We did not have ls1edit.. When ls1edit came out even the 346ci cars started putting out a minimum or 10rwhp more..

<small>[ August 04, 2002, 07:34 AM: Message edited by: VINCE ]</small>

Colonel

Gonna be hard (I didn't say impossible) to find hydraulic cammed engines making 500 RWHP with LS1 heads. As mentioned, at the point of going 400+ CI most folks go with the LS6 heads.

I believe I make about 530 RWHP. I believe with equal LS1 heads I would make about 510 but this is with the more radical than normal S1 cam, 12.2:1 C/R, and 1 7/8" headers.

VINCE

iTrader: (1)

Colonel are you saying that you cannot get a LS1 head to flow as well as a LS6 head? Remember we are still limited by the LS6 INTAKE..

Terry Burger

iTrader: (4)

I for one am sick of hearing about the LS6 intake. The LS6 intake works great (been shown to support 530rwhp), not to mention no one has come out with anything better. If you're running high lift and high RPM, the LS6 heads will benefit you. The 6.0L heads suck, too hard to get decent CR out of them.

XLR8NSS

iTrader: (4)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">
too hard to get decent CR out of them
</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Not with a big cube motor. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

John

VINCE

iTrader: (1)

Ok Terry. Lets do the math.. Everyone knows that you usually can get 1rwhp per each cubic inch bigger than a H/C 346ci setup. Lets use your setup as an example.. 440rwhp.. Lets use a 422 as an example.. 422-346= 76.. Now lets add on 76rwhp.. You get 516rwhp.. Thats about the avg you get out of most good 422ci setups.. We are talking Hyd cam as well.. This is true for the LS1 and the LS6.. Now we do have 346ci H/C cars dyno'ing 450rwhp plus as well. So that would give you your variances in the higher horsepower big engines.. What about a non-ls1/ls6 engine? How come I read used Nascar 350ci engines putting out 600hp.. What does that equate too in rwhp? About 510rwhp.. How many LS1's H/C 346ci cars are dyno'ing that? What is the limiting factor...? The DAMN INTAKE!!

kewlbrz

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by VINCE:
<strong>I read used Nascar 350ci engines putting out 600hp.. What does that equate too in rwhp? About 510rwhp.. How many LS1's H/C 346ci cars are dyno'ing that? What is the limiting factor...? The DAMN INTAKE!!</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">In Bill Jenkins Book "The Chevrolet Racing Engine", they refer to some 680HP 330ci small block chevy drag motors they built.

The cams used in the LS1 today referred to as Bigboy cams, are really moderate cams in the big picture, relative to traditional small block chevy power.

In my mind, and in an all out situation, the LS1 at 346ci, is capable of 700+HP NA with the right cam, rpm, compression ratio, and manifold.

I would love to see what an 346ci LS1 could do with a tunnel ram and a carburator, or carburators and a real bad boy cam.

Displacement is great, but its really all just a pump, and RPM in a smaller motor can acheive similar power numbers. Of course at the sacrifice of lowering the valvetrain life. Last I heard SW's 392 all bore was putting out over 500rwhp. I beleive that is probably one of the best examples of NA efficiency in the LSx motor. I beleive much more to be found with an proper intake.

Here is one example of that approach:

<img src="http://www.vetteguru.com/misc/C5R13.jpg" alt=" - " />

<small>[ August 04, 2002, 10:42 PM: Message edited by: kewlbrz ]</small>

VINCE

iTrader: (1)

I wish someone would make a better INTAKE.. Even a carb one would be nice for the LS1.. Now that is a awesome Intake.. Wow..

<small>[ August 04, 2002, 10:46 PM: Message edited by: VINCE ]</small>