I understand it's not the best head But it is the best head for the MONEY. Now if some of you all like spending money fine. But is 25 to 50 hp worth the switch if you already have LS3 heads. I got the money to spend and I won't do it, neither did Tim and my good buddy has the cash and the car to do it. I believed I could figure out some little slick S*@t and could get away with buying LS7 heads. Sorry. Tim said this 3yrs ago it is not worth the cost vs results. That was on a 416ls3 (he later went to a 454) with factory ported LS3 heads(with Mast intake) the switch would have been Mast LS7 heads and intake. It was not worth it.

 

On the simulator it made 748hp @ 7500rpms
500ft Tq @ 3700rpms over 600ft Tq from 5500 to 6100
Had to find it in my files. We listed flow up to .800 and added all the spec's we had. I was happy as that was the goal.

 

Any of you guy's can see what you got 4 free Dyno 2000 if you put the REAL Numbers in you can see what to expect. J has the newer version of Dyno 2000.

 

WoooW. English is not my first language but now I believe that we have good schools here in Saudi Arabia !

I read your other posts which seems nothing but attacking those aftermarket cathedral port heads !. Calm down, nothing wrong with you getting the FRH LS3 heads. LS3 are good heads for the money and really good heads for some applications. Even the aftermarket LS3 heads are nicer.

There are light drag race setups, street car setups, daily driven setups, road race setups, off-road sand, boosted/nitrous setups ... etc. We cannot simply go with what lil john just figured from other dyno post and because he is getting the FRH LS3 heads !

 

I got a check in for 40 racks I can buy any head out there. So buying a pair of heads that cost more and lose sounds better. You can't sell me on that BS. and they were not even Cnc'd ..LOL!!!


I know of a few simple little 408's with dope or Nos doing 8's in the qrt with Factory LS3 heads. Still comes out cheaper.
Nothing but love brother. Just putting facts out there.

 

Ah yes, the 700hp engine that's never been dyno'd or raced.

 

Nope but sitting in the garage....There are way more important things besides a car. Also if you didn't know you lose money when purchasing a car. 18 yrs in this game of chasing tail. I don't race @ Baytown anymore or West Mount Houston just go out to see friends and there builds.
Facts are Facts.
Well type your build or builds in and see how close it comes to the actual real numbers. I got what I needed 4 cheap and it ran quite well with the wrong valve springs.

 

If your going to spend the money on a lsx block, why not spend some money on a cam designed for your displacement and cylinder heads. I think ported ls3 heads would make great power for you, but with the larger bore why not step up to ls7 heads? The castings are out there and they really aren't super expensive. As far as cathedral a/m heads go....I'd save my money.

 

welp..... that's sound like Ford owners.. they chase dyno numbers instead of a lower E.T at the track which to me is what counts.
After all dynos is for tuning LOL.... who here knows James Short? Anybody know that name? Anyway James have one of those dynos that eats up rwhp numbers like Pac-man eating fruit.
One of my bud light drinking buddies have a 40X ci motor in his 6 speed 3450 lbs ws6. Car only puts down 460 horse to the tire according to James Short but in the real world the car runs 10.6 at 130mph on old wore out used slicks. Goes to really show how dynos are just dynos. Car is running out the box AFR heads.

KCS~ I absolutely believe what you said about the LS7 hanging on longer. As I visited the LS fest this past year I witnessed Ryan 99 SS 427 LS7 / LS7 headed Camaro 6 speed run low low 10.3 etc @ 133-135 mph over and over but like you mentioned it really was coming alive with the tach at over 7000 rpm.

So guys both can kick A$$ at the end of the day.
I find hanging on a big deal in a all motor application as I can't turn the boost up for better results

 

Your definition of a fact is a little skewed. You haven't dyno'd or raced your engine, but you know for a "fact" another head isn't going to produce better results. That isn't a fact, that's a fairytale.

 

So how dumb do you sound a 408 with 256 intake duration .757 lift and 11:7 compression. With a pair of TFS235 heads that stall at .650 come on man get of my D. So now you know heads better than any of the guy's I've spoken to as a Moderator. Fact.

 

There really is a lot more to making a fast car than peak power and flow numbers. Some people get it and some people don't. The latter tend to like LS3 heads haha.

 

A pair of factory heads just beat your god like TFS heads with a STOCK PORT and INTAKE. So theres your TFS heads in the trash, oh you do use these heads so you got to come up with some type of excuse on why those 2500 dollar heads lost...Oh the cam overlap ...etc. They Lost and still were cheaper. FACT.

And if a engine has more Power with less TQ re gear/higher stall TQ converter the darn thing to place the RPM band where it needs to be. If nothing else changes on the vehicle with a head swap. That's the simplest thing to do to make up for TQ. But the Ls3's didn't lose TQ they surpassed those TFS heads with a stock runner....

 

I run a set of ported LS3 heads on a supercharged 377 but, if I were running a 427 with a 4.125" bore I'd be running LS7 based heads. No brainer in my opinion. As for the TFS 255s, I'd love to have a set for my application.

 

This is my last words on this subject.
Ok a guy has a short block and factory heads that can make the power he or some 1 would like ( if more is wanted have them ported). So why in the HELL would anyone just BLOW 3 grand 4 a relative small gain. That goes 4 TFS,AFR,MAST etc. If this holds true might as well buy a Kenny Bell S/c with your money,it's a better money to Hp ratio. Ask some of these guy's what was the TOTAL COST of switching heads VS just having the stockers ported. 1 guy listed 3200 for a pair of TEA TFS LS3 heads and Honestly how much of a gain do you really think he's seen VS having the stockers ported.

 

I sound like a broken record as I say this..... The camshaft either makes or break a LS3 head combo. I can't say it enough and I'm tired of saying it. I study this $#*t everyday. I love making comparisons. Its my hobby. I have seen LS3 headed 408 motors make 585 horse at the crank and then watch the next company/engine builder make 620 with the same heads and intake and similar compression. What's the difference between the two ? The cam specs.....

What this proves to me.... I think I can spec cams for cathedral heads and do well even if I'm not a Ed Curtis, Kurt Urban, Pat G,Martin Smallwood, Brian Tooley or a Tony Mamo.
However I'm not go try to sit up here and spec a cam for a LS3 head combo do to seeing people not having luck at the track or on dyno day. They great heads but seem to be hit or miss in my opinion and it falls back to the proper cam selection. Why you guys think guys that bust @$$ with LS3 heads is so secretive about they cam specs.

 

Are you stoned again? You've been preaching on and on about how important it is to cam an engine correctly, but all of a sudden it doesn't matter? Lol. Neither head won, the new camshaft did. Anytime you drop 12 degrees of overlap, you're going to get a low-mid range boost. It's not an excuse, it's a FACT.

 

Yes it matters and both were cammed KCS. Put it like this:
A) heads cost 1200 bucks
B) heads cost 2500 bucks
The B head are Cnc'd & has 5 more hp and TQ while the A heads are as cast. Can't dumb it down any further than that. I understand that the the aftermarket head is a better head as far as extra meat and strength...etc. But to spend a few thousand dollars for 50 hp is not reasonable to anyone with common sense. Not hating on the aftermarket but there just making a factory part that will gain a few more horses but @ the cost of a couple of thousand bucks is the Point I'm trying to make.

 

Alright guys let's stop this argument!! I feel like a I got Ali in one corner and Joe Frazier in the other corner. I'm the ref!! LOL

Let's focus on the bore size of a 427 Ci motor. Bore size is 4.125 so that give us lots of options. Let's take full advantage of it. It's needs to breathe!! Without breaking the bank scenario let's compare factory let's compare a LS7 head to a LS3 head...
Which is best for the op?
Which has proven results at the track?
Which can run a smaller camshaft for better real world results?

Both can be had for a under a grand and both would need valvesprings upgrades.

 

That's correct but ls3 heads can and do make power. On that note so can peanut port bbc heads, and big *** rectangular port bbc heads, etc. So saying people who run rectangular port heads are stupid is a reach. I had tea cathedrals and was very unhappy with how the car ran. I'm building a stroker with square ports I'll get back to you on how my "I only know about flow numbers" heads work out. There is a time and place for cathedral heads, and rectangular, and square......of course your smart enough you should know that.