lil john

They cut the runner size down to help promote better velocity characteristics. While still getting better flow numbers with a smaller runner in turn generally makes more TQ 12 degree vs 15 degree. You must remember that everyone does not go to the local track...Some guy's just like knowing and bragging about how much power it made(to friends and coworkers) as there not race car guys. (Know of a young man on here who purchased a 2002 Z06 pulled the engine and replaced it with a 650 hp 418 with some suggestions) And just live a normal race free life. If your after a number such as ET's knowing how much you brung to a fight is The main thing. We can always tune a suspension or readjust the gearing or PSI changes to the tires,lower the weight to get a ET if you got power. You can make anything quick. If you got power someone will show you how to put it to the ground for good Et's if that's what your after.

Brian Tooley Racing

iTrader: (13)

The LS3 style heads are without doubt the best bang for the buck, no arguments here, I recommend them all the time, and I always recommend them over the TFS/Fast setup because of cost.

However if someone wants to make the best power they can, I'll put them in a set of custom TFS heads, because I haven't seen the ported LS3 heads perform as well.

When I was at TFS I saw a set of LS3 heads tested back to back on a 402 against the TFS 225 heads. The TFS heads did have a Fast intake and it might have had the step ground out of the Fast intake port, so no comparison in cost. However the TFS heads made 30 hp more than the stock LS3 heads/intake. The TFS 225 heads did have the optional 70cc chamber to match up with the LS3 chamber size, and the 70cc chambers may make more power due to their shape, provided the same compression is utilized, if that makes sense.

I also saw a set of TFS 235 heads/Fast intake tested against a set of box stock LS7 heads/intake on a 440 cu in engine (4.125" x 4.125") and the TFS heads made 20 HP and 30 lb/ft more torque.

Both sets above did have the valve job properly blended, so there's some power there. Bottom line is for most hydraulic roller LS street engines, the TFS cathedral port heads with proper blending and port matching will out power almost any GM casting. However for the price, it's hard not to run the GM castings...

speedtigger

iTrader: (16)

Hey Brian. In this test, I assume both heads utilized the same camshaft?

Brian Tooley Racing

iTrader: (13)

Same cam in the 402 test. The 440 test they used 2 different cams, one was conventional and one was the GMPP cam made for LS7 engines, I can't remember much about the second cam other than it had a huge split. The TFS heads made more power everywhere with either cam.

That testing only reaffirmed my belief in efficiency, as measured with a simple coefficient of discharge calculator or spread sheet. We saw it time and time again. The same 402 testing had a set of AFR 225 heads with 2.08"/1.60" valves that flowed about the same as the TFS 225 that had 2.055"/1.575" valves, however the TFS heads made 20 hp more. Muscle Mustang tested the Ford TFS 205 Twisted Wedge heads with 2.02" intake valves against the AFR 205 heads with 2.08" intake valves on a 408 and the TFS heads made more power everywhere, same thing, efficiency.

Airflow at each lift point/Valve diameter x Pi x lift = Coefficient of discharge

=(C270/(B270*3.14159*A270)) is the actual formula, where A cell is lift, B cell is valve diameter and C cell is airlfow.

Bear in mind that many get misled with flow numbers from a Superflow 600 due to it's inability to generate accurate flow numbers like we talked about before.

lil john

Would a good Cnc help the stock heads compared to the test given? As one was bought prepared for combat while the other is rough and a mass produced product. I understand what your stating Brian. That comparison is like a Ford VS a Ferrari. One was made for track day will the other is a normal commuter car. On either the LS3 or 7 head.


I got you on the efficiency of the small port head. But due to a raw runner it's not really a fair test .

Gray86hatch

iTrader: (83)

My FlowTech induction hand ported ls3 heads went 9.50 on a 418 and 9.24 on a 454 with at the same weight and mast 4500 intake. Hyd roller for each motor.

There was more power in the heads but I really needed a much bigger head to invest more in the ls3 was not going to happen.

Tim

Brian Tooley Racing

iTrader: (13)

The LS7 heads come fully CNC'd from GM, so that's apples to apples.

Naturally the LS3 heads will benefit from porting, but will they gain 30+ hp without additional milling for compression on a hydraulic roller cam 402 using a conventional style EFI intake? I haven't seen a program that will.

Brian Tooley Racing

iTrader: (13)

That's excellent performance from a GM casting.

The TFS 245 heads have run 8's N/A on a hydraulic roller cam, #10 on the all time N/A list, Coleman Roddy.

https://ls1tech.com/forums/drag-raci...-n-any-cu.html

speedtigger

iTrader: (16)

It is just hard to imagine that a larger engine that size would prefer such a small head. What was the RPM range of these engines? It seems like an engine that you would want to peak closer to 7000 RPM would want more head. What this a plastic intake engine?

Brian Tooley Racing

iTrader: (13)

Yes, Fast or stock LS3/LS7.

It kills me that a 245cc head with a 2.10" intake valve is considered "small". I remember when a SBC head that was 210cc was "big".

There isn't a professional racing series anywhere in the US that uses the largest heads available, they always use the most efficient.

lil john

How you been Tim, hope things are humming along @ the garage.


I'm with you Brian, my thing is this most people will say go purchase a head and will not see past the fact that the stock heads can make up 800+ N/a so why go buy heads. Just get them some love. BTW. WCCH LS3 head made 518rwhp with a stock block C6 and a off the self cam(What would a custom cam do). I'm willing to guarantee they will make 30+ hp ported on a typical 408 with port work vs a stock set. Factory intake sucks and will hold back a head that flows 370 @ .650 on a 4.030 bore.


Speedtigger: The only problem with the comparison is the plastic intake
The Cat style heads have the lower and mid lift but on the upper end of the scale they peak @ around .650-.680 lift on MOST of them. With flow in the 360 range and we know a FAST can not Deliver that much. So now on a good LS7 Head that gets 380 @ 650 we are killing power. And how much does a GOOD FAST ported intake flow around 350 ported, perfect for the Cathedral style heads. One head is able to reach it's potential while the LS7 heads have 30 more CFM needed. Every cfm adds up to around what 2.2 hp so 60hp is missing from the jump with a FAST intake PORTED.

Gray86hatch

iTrader: (83)

Also mine is driven to the track. Cam is easy on parts. 5000 miles on the springs and they were still perfect.

Its not just the heads. Everything else must work together. Comparing dyno # is not the answer. Unless the same effort is put into either combo it is a waist of time comparing them.

Tim

HISS

iTrader: (52)

There you have it.....I think it's fair to say we all respect Mr Tooleys opinion based on the years of r&d camshaft design and cylinder head design. I'm still sticking with ls3 heads...I'll add 20-35 hp more jet if I feel the need to go faster vs spending 1000-1500 more dollars on a dismal performance gain.

speedtigger

iTrader: (16)

Inflation.

Brian Tooley Racing

iTrader: (13)

Imagine testing CNC ported LS3 heads back to back on a really large LS engine with a high flowing Mast single plane intake that will really let some LS3 ported heads shine?

It's been done, only the best ported LS3 heads gained 30 hp. On a 402 with a stock LS3 intake you would be lucky to see 20 hp.

http://www.hotrod.com/how-to/engine/...er-heads-test/

That was tested on the above 468 cu in engine as well with the better Mast heads, and the Fast only lost 30 hp compared to the Mast intake.

Brian Tooley Racing

iTrader: (13)

Also note that some Mast square port LS3 heads were tested back to back against a bunch of cathedral port heads on a 408, and the square port heads did not come out on top.

http://www.hotrod.com/how-to/engine/...der-head-test/

blk00ss

iTrader: (66)

lil john

Went out to eat with my college girl.....


I'm with you Brian.

Tim said something good as usual: It's not just the heads. Everything else must work together. Comparing dyno # is not the answer. Unless the same effort is put into either combo it is a waste of time comparing them.


And that was Mast 12 degree heads vs Stockers. Is the money worth it VS port work. ..Also everyone does not want a small cam and I KNOW 4 a FACT I will Never buy a FAST/MSD intake. They don't meet my requirements as far as a engine goes....Never Hurt FLOW...Keep gas in the chamber ...fire..exhaust... so restrictions are never apart of a engine(money is the factor). Just port the factory intake and not get hijacked.


That cam was 4 a baby(also off the shelf sucker cam), my cam is bigger than that with a 408 with A/c and ran darn good in bumper 2 bumper traffic...A/c not hooked as of yet. Let's try around 750 lift how much hp would be on the table then. I can cheat TQ lost with not using a FAST intake.




You said it for me and you said it in your post above. Y go buy a aftermarket head and lose $$$$.oo and only gain 10+ hp when a factory head will work. Another thing how well do those Cathedral heads flow past .700 if you want to have some dream number such as 400cfm with a small bore head or Just want a crazy solid roller....Factory can go there also with either head. And the runner stay relatively small.. under 272cc's. I think mines need to be tested on a 4.185 bore and see what it does with a 266cc runner. I think 400cfm could happen, 370 @ .650 and they carry over to .800 lift on a 4.070 bore. (May get a dream number while thinking about it ) That's been documented*Chris @ SAM. I would love to see a solid roller comparison on the same 408 with some *cojones and see how that would have turned out with a Super Vic/ Mast / or Holley high rise intake....With all the heads listed and stock ported ls3 heads were used. Hmmmm.
I'm proud of the fact that a 175 dollar head can supply any need I got and will be within 30 hp of the best.




Cool thing is you can have your cake and eat it to with Factory or the Aftermarket...

Tuskyz28

I'm in with you in the popcorn.... just don't forget the bud light.

FLYZNTN

LOL! This is a rerun or a remake of the same thread that pops up every 6 months or so. I wish I had an extra few thousand laying around so I could run a set of cathedrals (assuming I could find an intake that would work with my Whipple) just to feel the difference. It'd be a fun experiment but I'm not made out of money and my damn car is too expensive already