white01ss

iTrader: (37)

LS6 Heads: How much power can they take before they start lifting?

The purpose of this poll is to find out where LS6 heads start having problems keeping a tight seal on the combustion chamber. As mentioned below, this applies to both 243 and 317 casting heads. Bonus points to voters that have lifted a head.

If you vote, please answer:
lifted a head?
what casting?
using head studs?
max power level?
injecting h20/meth/alky?
how much boost?
static compression ratio?

blue00ZZleeper

iTrader: (5)

I to am very interested in this seeing as how I should get my PRC Stg 3 LS6 heads tomorrow for my 370-D1 build. I've seen quite a few cars on here make between 700-800 on them. They have a pretty thick deck which is good from a stock casting head and ovbiously good for boost. The LS6 and 317 heads iirc are some of the best besides aftermarket high dollar heads like AFR's or TEA's.

white01ss

iTrader: (37)

I did an exhaustive search yesterday but couldn't find much about LS6 GM heads. I even checked a few of the other LSx forums. Found lot's of discussions of the limits of this or that block, but not much about heads. This all started because somebody in the industry told me that LS6 heads start lifting around 700 rwhp or 15 lbs of boost. Funny, after I posted this poll it became the first result on Google searching for: "ls6 head lifted boost".

LS1RedZ

iTrader: (19)

Im currently running 15psi and made 754rwhp with my TEA LS6 heads. Im using head studs as well. Compression is around 9.1:1 and im using straight pump gas. Havent had any issues yet. I dont think I should either. Give TEA a call.

dschmittie1

iTrader: (64)

4DRUSH not sure if he is on here but is on corvette forum has gone 8.90 with stock LS6 intake and LS6 heads with a YSi

white01ss

iTrader: (37)

Thanks. Beginning to think the "weak" GM head myth was spread just to sell aftermarket heads. "Don't go over XXX or that GM stuff will break!"

Novistar

The blower is paxton novi 2000, but you are correct about the heads!

fatmat80

in a week or two i will be installing my prc stage 2.5 headed forged 347 with a d1sc and running 12# of boost thru it..from all the people and shops i have talked to they say you should be fine as long as you use arp head studs, good gaskets and your surfaces are square...but we shal see..

There are a few people in my area that are running low 600 rwhp and have had no issue to this point..

blue00ZZleeper

iTrader: (5)

Well I just got my stage 3 LS6 heads tonight. They look pretty awesome. 311 int 233 exh. I should be feeding them 16ish psi hopefully.

fatmat80

^^who ported them?

blue00ZZleeper

iTrader: (5)

Patriot performance. They look badass!

stevieturbo

These LS1 heads seem to be doing well.

http://forums.corvetteforum.com/c5-f...ls1-heads.html

white01ss

iTrader: (37)

Nice find. Mid 9's with 16-17 psi of boost and stock 03 vette heads, not too shabby. It's rare to find a racer in the 9's with stock GM heads. I guess most upgrade for more power before there's a problem.

Still no report of a lifted head, though. Bob, you out there?

dschmittie1

iTrader: (64)

well I am hoping my home ported 243 casting heads go in the 9's Maybe it will go in the 9's first time out tomorrow night.

LS1x2

iTrader: (11)

I wouldn't be afraid to push unmilled ls6's to 900rwhp. I'm making 713rwhp on mine with stock gaskets/bolts. They have never been off. Detonation is the cause of heads lifting on these motors more often than not.

white01ss

iTrader: (37)

Can't find a reason not to think they could handle 900. People running 8's and 9's with these heads.

Photochop

iTrader: (74)

You also need to remember that the LS6 head and 317 head are VERY similar and theres guys known for pushing 800-900 out of those as well.

white01ss

iTrader: (37)

Thanks for that. Added note in first message. Looks like 800-899 range is gaining ground. Keep the votes coming...

fatmat80

glad to see thses results makes me feel reel good about my decision to go with my stage 2.5 ls6s

white01ss

iTrader: (37)

Saw a few other cars with 800+ rwhp. They should come vote!