ChrisUlrich

When you're trying to make 430-440whp or trap 120mph+. Do you really need LS6 heads? Or if I just use the heads off my 2000 LS1... would that be enough?

I won't be going with a FAST Intake. Ported LS6 intake at best...

But I will be doing with: Kooks LTs, dual electric cutouts, and a ported tb.

92 Z28 LS-1

iTrader: (1)

I just put some LS6 heads and a LS6 intake on my LS1 about 30 minutes ago. The heads i ported myself, i believe they should flow about 300cfm and with a 224/230 cam I hope to hit 400rwhp. I can let you know exactly what i am going to make when i go to the dyno in two weeks. Here is some stock flow data if it helps:

stock LS1 243cfm @ .600
stock LS6 278cfm @ .600

ChrisUlrich

I hear what you're saying... but at what point does it NOT matter? Like... are the castings completely different from each other?

If they are different... do I need LS6 heads to make my goal much more feasible? To me 440whp on a large cam and a good set of ported LS1 heads seems pretty reasonable. But if I did the same kinda port work with a similar cam... would I make more power? Using a ported LS6 intake of course...

Get what i'm askin?

Dom

iTrader: (2)

Compare the flows at .200 and .300. LS6 heads also have smaller chambers for more compression. So you'll get more torque from cams. I contemplated getting a pair of stock LS6 heads myself. I don't know if it's worth it. I guess it all depends on how cheap you get a pair.

Doc

iTrader: (9)

The answer you seek ultimately comes down to pricing, availibility (Local Talent) and the depth of your walet. Deals abound on this board and many others for those with cash, e cash, or otherwise e denairo to go. Many folks have found execellent price point/performance deals on 5.3's, LS6's you name it. Do care to go retail or are you patient enough to go into the trenches and make somebody's day by forking up hard cashe on an instant? Truth is, for this (GEN III LS1) motor, the people are really in the cat bird's seat when it comes to options for heads. Sorry for no real direction in this post. Explain more of where you are coming from finacially/time frame needs, and you will probably get more direct answers that are tailored for your situation.

sidewayz28

iTrader: (24)

i threw on stock LS6 heads when i did my 90/90 swap.. there a better head design then 241s and any other previous ls1 heads

ChrisUlrich

I hear what you're saying from the financial stand point but that's not what i'm asking. I know LS6 heads aren't very pricey at all. But for the goals i'm looking at. I'm wondering if I even need them.

stealth71

iTrader: (15)

Lately I have been reading about the stock LS6 valves. I think they might make a big difference in valvetrain stability that is often over looked. Most aftermarket 243 style castings don't some with the hollow intake and hollow/sodium filled exhaust valves.

99 Black Bird T/A

iTrader: (4)

Chris, I think part of the answer to your question depends on what sort of supporting mod's you have.

I've been away from the scene for a little while but I'll give you my .02 worth.

I'm guessing you'll have or will have a good set of headers, all the basic bolt on stuff etc. Quality programing will help get the most out of the car. Mail order is ok but being able to let a good tuner work with the car on the dyno and street will probably get you the most results.

My car has an older set of ported heads and a 224 cam and is about 12 to 22 horsepower under what your goal is. Many cars have made as good or better etc.

I'd probably skip on the ported LS6 heads due to cost but ditch the LS1 heads in favor of using a set of ported 5.3 heads as the basis for your set of ported heads. I think this at least deserves a look.

As for the ported LS6 intake, often they will lose some bottom end and only gain ~8rwhp on the top. Depending on what porting the LS6 intake will cost, that might be better spent else where. A good ASP (or similar) underdrive pulley would probably get you about the same gain and it would be thru the entire rpm range.

Cam selection will play a part of course.

Personally, if the car will see street time and lot's of daily driving, I'd suggest the best heads you can get with a reasonable cam.

Good Luck with your project.

B-Bird

sidewayz28

iTrader: (24)

why go with 5.3 heads over 243s?

99 Black Bird T/A

iTrader: (4)

Most porters tended to get a bit (a few cfm) more flow from the 5.3 intake runner in the past. The 5.3's also offered a bit more compression without having to mill the head. This could give more Piston to Valve clearance all things being equal for the same compression. Depending on cam selection a little more P to V could make it worth while if big cams are being considered.

Things may have progressed with the LS1 head porting to the point that 5.3 no longer offer worthwhile advantages anymore.

If a good set of welded up 6.0 heads CNC'd back into "LS6" heads can be found at a good price those would be worth looking at. One of the sponsors (I forgot who, it's been a while) was doing that at one time.

ChrisUlrich

5.3 heads are the best heads to go with ya think?

92 Z28 LS-1

iTrader: (1)

I have a friend that had GMMG install their Phase IIx package on his 02 WS6 and they used 5.3 heads. They are CNC ported and milled with larger valves. He is making 436rwhp with 5.3 heads and a cam, bolt-ons, full GMMG exhaust and customig tuning. It also has 11.75:1 compression.

I spent about $600 on my new LS6 heads with 918 springs and about 10 hours of porting. If i ever get another set of heads i probably would go with Livernois Motorsports stage 1 or 2 heads.

Livernois stage 1 heads are only $995 and flow 305 cfms and handle .580 lift.

99 Black Bird T/A

iTrader: (4)

Chris, I think you can make the 430rwhp mark without LS6 heads. I'd talk with some of the sponsors over there >>>>>>>>>>>>>>>>>>>>>
and see what they think for your application.

Ask yourself if you'll be upset if the car makes 430rwhp instead of 440rwhp. If your really set on 440rwhp, the LS6 heads will be a safer bet.

If your ok with say 430rwhp then I'd really look at a 5.3 set up.

One other suggestion would be to take a look in the racing section of the board and see what set ups the racers are running these days. Depending on what time you want your car to run, that can be helpful too.

Good Luck with your project.

SilverC5Vert

My car with Livernois Stage 1 heads and a 224/228 114 cam, longtubes, and offroad x-pipe made 420 rwhp / 390 rwtq, but ran a best of 12.3 @ 119 MPH on street tires. I've seen people make great power with their head and cam packages.

-Rick