ShoddyHog

iTrader: (1)

I'm laughing at you. Well, technically, I'm not laughing at you...just one particular statement.

midevil1

iTrader: (17)

LS3 and L92 heads will stomp a mud hole and walk it dry in the 243's and 799's or any GM cathedral port..

My 370 made 504whp with a 231/239 cam. Thru a M6 and 5.13 gears.

I don't believe they can make the lowend that a cathedral can produce, but for all out best performance. You can't beat the rec. port heads.

lemons12

iTrader: (71)

Well Instead of laughing why dont you post something and show everyone what is so funny about my statement, I'm sure the more informed would love to know.

A nice cathedral port head will make ls3/l92 head look cheap, no pun intended.
Not only will they make more peak power, they will make more power under the curve and everywhere else, in addition to having improved throttle response/crispness/tip In/etc.

I'm sure you are pretty set on defending the gm rectangular heads... All of which will be shot down. I love ls3 heads, for what they are.. An aborted stock casting head. I was going to run them but after research quickly steered clear. The port velocity just Isnt there. Valves are entirely too large for anything under a 408 that is to be enjoyed on the street, or seriously raced at the strip.
Not to mention the limited spring selection, as well as Intake and cam selection.

Alright.. You guys got to get me some of whatever you're smoking. A nice set of aftermarket cathedral ports will outperform an ls3/l92 head everywhere, period. And this implies even more talking about 3.9" bores and 408 and under motors.

Have any of you guys making these claims seen Dyno and track times of nice cathedral heads vs l92 style heads? There isn't much of a comparison similar setups, within reason, cathedrals will make 30+rwhp more.



If anybody assumed I'm talking junk ls6 or 5.3 stg 2.5 ported heads when I said nice heads... The jokes on you. Nice heads... Afr 230/205tfs 215/ etc etc..

lemons12

iTrader: (71)

Be easy on last post typed from phone at work.. Excuse errors or a hard to read sentence.

ShoddyHog

iTrader: (1)

Because I'm too lazy, and don't care about the misinformation posted here.

I've been running my 6.0/LS3 head combination for over 50,000 miles with two different cams, and my only suggestion to the others reading this thread is if your 6.0/LS3 combo does not have good street manners, makes shitty low end power, and doesn't perform, you need to find a different cam vendor and/or tuner.

ShoddyHog

iTrader: (1)

You typed all that on a phone from work? I want that job.

LT1Formula007

iTrader: (66)

Lemons12: Remember though, rectangular heads don't need a huge cam like some cathedral heads to make big power. A 231/237 .600 114 is considered very large in a 6.2 ls3 setup.. That would be considered a slightly aggressive cam In a cathedral 346 motor.[/QUOTE]


Oh I know. I was just saying that if he went with an aggressive cam, It's really gonna want to live in the upper rpm's and the LS3 Intake doesn't flow as well in the upper rpm's. Some cars have a tendency to fall off in power up high. Especially in the top of 3rd gear... But many things can contribute to that as well tho.

Like I said, My buddy has the TSP 231 236 .644 .613 112 Cam in his LS3, and it runs great and made 441/425 (rwhp/rwtq.) And again like I said it drives very well, But it does fall off up top tho. He needs a ported ls3 / FAST intake or a single plane - Just something better to compliment his setup. His dyno graph kinda leveled off up top. It makes good power everywhere, and fwiw I am impressed being "cam only" and making the same power my Brothers H/C/I/LS1 is making.

**Oh, and theres Alot of good opinions in this thread.

midevil1

iTrader: (17)

And I said GM castings...THERE IS NOT A CATHEDRAL GM CASTING THAT CAN COMPARE TO A REC. PORT CASTING. PERIOD END OF CONVERSATION. You are gonna need the BIGBOY 225 to 245 cathedrals to flow with the LS3's.

I am using 317 castings in my latest build for a 1000 to 6500 powerband. Yes, they have considerable porting and the valvetrain cost me over 1K, but the heads will not have any short comings. This is going in my HD for strictly towing and make a solid 400whp.

The bottom line is the rec. ports will get the OP the horsepower he wants and it will be the cheapests and easiest route. Since aftermarket castings are 4 times the cost of GM rec. ports.

1lejohn

iTrader: (9)

Why has GM put them on the trucks and new Camaro then?? Because they do make more power and torque more then a ported or stock GM cath. casting. I'm not comparing them to an aftermarket casting.

The car is a weekend warrior that is driven on the street. With a 60e or 80 e trans in the car it will be all good.

1lejohn

iTrader: (9)

Amen brother. Anyone can get a turd to run with aftermarket castings.

LT1Formula007

iTrader: (66)

Very nicely stated. And I also agree. Stock for Stock and the most Bang for the Buck... The LS3's are gonna outshine a Factory GM Casting any day of the week.
But when you compare an all out Ported Aftermarket (TFS/AFR/All Pro) vs A Ported LS3, Then it becomes more of an overall setup to determine how the engine is going to act. It may be lazy, or it may come on strong. But that's all in the attention to detail. LS3 heads are very nice for what they are. And I was impressed by the fact my buddies cam only ls3 TA made the same power as my brothers H/C/I/LS1 TA, But that just shows their potential. However, I have seen them "Really" shine on the larger 408+ CID engines too. Which makes me feel as though they are better matched for a larger CID Engine as opposed to a smaller. But I don't have any first hand experience personally to distinguish that, other than the fact my buddy had good results with his car. I do however know that they make good power in stock form on just about anything 6.0l and up.

**Another comparison, lol. But I have another buddy with a 2011 Camaro SS with a G6X3 cam, Land Speed Ported LS3 Heads, a ported L92 Victor style intake, 4150 Style TB, a Carb Hat Elbow on the FAST TB, running on E85, and it's making 53x rwhp with a stock shortblock. The pistons are flycut to clear the cam, but nothing was changed from the stock LS3 bottom end! I thought that was pretty impressive for it being done on a stock shortblock.
Just shows the LS3 Heads can get it done when properly matched up.
Oh, and his car pulls good from just about any roll. It may be a little lazy down low, but not as bad as I would've thought.

1lejohn

iTrader: (9)

Good info by all the posters. I think the OP should follow the advice posted and add an intake and some other parts and he will be good to go. I would consider changing cams. Just not a fan of the MS shafts. The LS3 heads will make good power and have good driveablity they will make more power then the 6's . It comes down to the $$$ as always.

LT1Formula007

iTrader: (66)

^^Agreed!

lemons12

iTrader: (71)

A cam is only shadowing the true problem. Those heads just flat out move too much air, they can't keep the velocity up.
HAHA.. Was a pain! Lol
Ummmmm.. If that is your point, why are you arguing? I agree 100% with that.

If you guys think of a gm casting when I say nice cathedral head, the joke is on you. Lol

And yes, to duplicate pure flow numbers you would need those heads... But to outperform them, you wouldn't.
Hard fact: The l92 heads simply don't live up to their god like flow numbers. Period.
Not to count the fact they have short comings that the dyno or track times dont show.
There are so many other factors that come into play with how well a head performs.. If you don't know this, you shouldn't have even posted.

The l92 heads were originally going to be a high performance/rpm head for the Corvette. In the final stages thy ended up changing plans, hence the ls7 heads.. We all know gm doesn't like scraping work, especially one with this much r&d at the time so there is where the heads went, they had nothing else to put then on.they were intended to make power at high rpms, in a large ci. Motor..

Without a doubt.
Ms3/4 and a rectangular head would be horrible, plus I highly doubt it would clear.

lemons12

iTrader: (71)

And BTW.. For anyone to think I'm hating. I have an l76 on the way.... Aluminum 6.0 with l92 heads. I will be running that setup and expect it to perform very well. Mid 6s on motor is my goal, 3400# normal da. However, I realize that I made a compromise and I'm fine with that compromise... It is why I got to save 2,000$ and not have much/any compromise. But not everyone would be ok with that compromise.

But to tell someone that obviously cares about how a car drives around town, with a 6 speed, that ls3 heads will get him what he wants is not right. They are lazy on stock cube motors under 4000rpms compared to cathedral heads. Period.

2QUIK4U

iTrader: (7)

LS3 heads do not have to be a dog down low. I had ported LS6 heads done by a very reputable company on my old SS LS1 vs. a 6.0 in my G8 with L92 heads that were stock with only a valve job. Cam specs were pretty much identical. SS had 230/236 mid 600 lift G8 had TSP 229/236 mid 600 lift as well. SS made 440/400 through a M6 and 9" rear. G8 made 435/405 through an A6 with 3200 converter and 2010 Camaro diff. Teh dyno graphs overlayed on top of each other a almost identical. SS had a FAST 90 and the G8 had a ported stock intake manifold. Headers were both 1 3/4 Kooks. Both cars had dual exhaust, UDP, etc. Overall very similar setups. Both cars had good low-end, midrange and top end power. Both cars had excellent street manners and throttle response. Overall good power can be made with cathedral port or rectangle port heads. It is largely in the particular combination of parts and the tuning.

1lejohn

iTrader: (9)

The l92 heads were originally going to be a high performance/rpm head for the Corvette. In the final stages thy ended up changing plans, hence the ls7 heads.. We all know gm doesn't like scraping work, especially one with this much r&d at the time so there is where the heads went, they had nothing else to put then on.they were intended to make power at high rpms, in a large ci. Motor..


I wish we had an intake to take advantage of them LOL

My car peaks at 6000 with a L92 intake. Don't know the numbers below 4K thats our stall speed. I do know that I can street drive the car any with an auto. It has no issues what so ever. The manual trans should be fun. The only problem that I have is when the convetor is locked and you hammer it, if the vert doesn't unlock its a dog. Drop down to 3rd or 2nd hold on.

lemons12

iTrader: (71)

Yea.. That's a seriously low peak. What do you think it would be with something that could breath up top?

Does the fast help make it breath better up there?

1lejohn

iTrader: (9)

Yea I'm wondering about the Fast. On the 383 a Fast 92 carried out to 6500. I'm thinking it would help. With Eds cam the car rev's so fast it feels like its making power till 7k in the lower gears. Last night at the track I could really feel it lying over. When the convertor locks it helps but

I never had a graph from our first dyno session due to alot of problems. That was over a year ago. We had the feeling the car was running out of steam but not like this. Flaco has had some sucess with the Vic jr's . He guessed 40-50 more HP.

Looks like a winter project if the funds are there. The Fast would be easiest to do. I'll post results if I do it. Still haven't tuned the N2O system I reworked it over the summer and haven't used it I suck LOL . Tried it at the dyno and the window switch had a bad ground and wouldn't power up.

The N2o just makes the problem worse on the top end the car revs faster and I have to use OD. Oh wwell right now I have a nice street car.

lemons12

iTrader: (71)

I absolutely despised the fast I had.. Got a ported 102. The size was just so big It made being in there working even more of a pain.

That is one reason I'm going with the rectangular setup.

What are the options and price on the vic Jr setups?