“Since we developed our 235 head, we have always wondered how the head would compare to an LS7, factory CNC ported, titanium valve package. We used our 440 CID LSX dyno mule engine, with 10.8/1 compression with 70cc chamber, Lunati 262/270@.050, .629/.629 Lift, 114 lobe separation cam, and 90 MM throttle body. We bought the GM heads and intake manifold, and used them out of the box (other than a spring change to accommodate the increase in lift), the same as the FAST intake and 235 TFS heads we installed. We kept the camshaft, compression, throttle body,as many things constant as possible during the comparison so that we had valid data.



The results are interesting. The 235 heads and FAST intake combo made more area under the curve than the LS7 heads, while giving up a small amount up top. We attribute the top end power to the lightweight valvetrain, and also the larger intake port volume (260cc) and shape of the LS7 cylinder head. Even though the LS7 head does make good power up top, it does not offset the area under the curve that the 235 head makes below 6500.



The nicest gain we saw was in the torque curve, where the cathedral port head made 35 ft/lb more. Keep in mind that this is with a 440 CID engine, and obviously results will vary due to bore, stroke, cam selection, etc.



One last item to note, this is with a standard set of LS Jessel rocker arms with 1.7 ratio used on the TFS heads, vs. the factory 1.8 ratio rocker arms on the LS7 heads. We will retest the TFS combo with a 1.8 rocker arm for an apples to apples comparison, which may result in a touch more additional power for the TFS 235 heads (it also may make no difference-we will find out when we dyno itJ).



We wanted to share this information as we own two Superflow engine dyno’s , and know that a lot of LS1tech members are always curious about combo “1” vs. combo “2”. We always learn a lot from our testing and R&D, and hope you can as well. If you have suggestions on what we should test next, post it up and we will evaluate what the members would like to see.





“Trickflow Tech”

 

I applaud your efforts.

But this test is not true test of cylinder heads.

As everyone should know, a camshaft should be matched to a cylinder head. If you were testing a TFS 225 vs a ETP 225 then I would be on board with you. As it is you have a cam that is proven to generate big numbers with you heads and you stick it with a head that will want a completely different set of valve events. Honestly I am shocked that the LS7 heads did this good. Brian Tooley and I had a conversation about this several months ago and he said a test of this sort was in the works. I asked him then to please run a different cam on the ls7 heads than the TFS stuff.

I propose one more test. Very simple. Run the Katech/GM cam in this same motor. Either one will work, either the 220/244 or the 233/276. These are not magic cams or secret in any way. I would be interested in what the results were then.

 

Just looked closer to the curves. In a drag race I bet the ls7 car would win.

 

This is just one of the first tests we have made with this motor. There are more to come in the near future. We plan on testing different cams as well as intakes. At this point, we just wanted to post up some results of what we found in testing.

 

You will NEVER suit everyone.

Regardless of what you do, you will ALWAYS find the guys who say it was an "Unfair" test...

If you swapped cams, then you would have guys jumping in saying "Its not accurate, you swaped cams"..

Just keep making a great head. Although, I think its time for you guys to step into the LS7 castings. Being that nothing is made with the cathedral port design anymore, I would think you would want to stay current with the times..

 

To be quite honest with you, I think it would be impossible to do an apples to apples test on heads this different from each other.

Honestly I would still choose the ls7 head.

 

How in the world did you come to that conclusion??? Because of the few extra HP at the last couple hundred RPM?? I understand its almost 50hp at 7K, but you just wouldnt shift the lower hp car at that rpm.

Drag races are won/lost based off of highest average HP, and power delivery in the given RPM range.
Based off of the graph, the car with the lower HP and torque would have a significant lead by the time the higher hp/tq allowed the other car to gain momentum on the big end..

I would take the couple less HP any day of the week, based off of the power under the curve..IMHO

 

If there was an intake that was worth it, I would have gone with an LS7 head as well..
Unfortunately, no-one has stepped up to the plate..
I agree, you can never do an apples to apples test. But this does give you a good example of what type of power delivery to expect in a given rpm..

 

If you shift the lower Hp car earlier in the rpm range you will end up at a lower engine speed and therefore making less hp. Say you shift the ls7 car at 7K and the TFS car at 6500. The ls7 car will always be working 500 rpm higher in the power curve. Compare the numbers at those points.

Actually the manifold is one of the biggest reasons I prefer the ls7 heads.

I just want to say it is a good thing to be having this discussion. I think everyone can learn something, me included.

 

^^ I just raced a friend last week with a built 347 in a C5 and his power starts falling off at around 5500. He made 470/495 (yes 495 rwtq in an N/A 347). He was shifting at 5500 to keep it in power band and that thing was dead even with me on a handful of runs. It's all about utilizing your power band.

 

the fast intake is the MAIN reason the TFS setup fell off a cliff @ 6500..... the intake is choking to death past there on a 400+" motor with great flowing heads. its just all about the total combination, not just peak #'s too....

 

Enjoyed the test results guys....no you cant please everyone, and IMO they are in line with what I would have expected. At lower RPM's the cross section and short intake runners hamper the LS7 performance (while the smaller cross section and much longer intake runners on the FAST are in their element), so none of this comes as a surprise.

That said, this post's figures are mathematically impossible on multiple levels, the main one being the RPM its claimed and the fact this small displacement engine makes more TQ than power. The shop that handed this dyno sheet out should have been scratching their heads or the poster, owner has his facts completely out of whack.

This stuff is math guys....some stuff can happen and some stuff can not....this example is the latter.

Tony

 

then the tfs heads make more power if u look at it that way huh.

 

was the ls7 intake ported and what about the fast intake?

 

The dyno graph shows both engines making more horsepower than torque.
It is a pretty lame comparison though.

 

They were building this motor to make tq. Synergy pumped it out using some of your AFR's Tony. I saw the graph myself and and was around the whole time this motor was getting built and iv'e been around to see a lot of cars on that dyno and these are not the typical #'s it pumps out. When Rick told me the cam specs I didn't know what the hell he was thinking and thought it was going to be a flop but I was way wrong (turns out he actually does know some things about cams). This thing runs hard and is an absolute sleeper with the cutouts closed.

 

I was referring to the 346 quoted in that post...NOT the TFS / LS7 comparo

Tony


A 346 couldn't fill the cylinders enough at a low RPM to make that type of cylinder pressure (enough to generate the TQ figure your quoting....I don't care who's heads were on the engine). The only way a small engine like that could potentially generate that much TQ at the wheels normally aspirated (and even this is a stretch) is with race gas and much higher compression ratios and a huge cam....BUT, torque peak would happen at close to 6K and then the engine would make stupid power upstairs because the TQ curve would naturally carry flat well into the 7K+ range producing crazy power figures at that RPM as a byproduct (HP doesn't really exist....its a mathematical function of TQ and RPM)

Anyway, I don't want to derail this thread and Im not trying to call you out on the results (I assume your quoting what you heard)....just trust me its impossible and feel free to contact me if you need further explanation. Who else witnessed the laws of internal combustion physics being broken?....I would love to see the graph.

Just PM me....don't hijack this thread

I still think the test these guys did was informative and it shows that the cathedral design is certainly not dead....in alot of applications it still makes good sense....especially full weight street cars running hydraulic valvetrains which somewhat limit RPM's.

Thanks
Tony

 

honestly what this comes down to is the price per hp ratio...... how much are these trick flow 235's and how much are these ls7 heads from GM???? obviously the ls7 heads are way cheaper then the trick flow heads by a long shot. and obviously anyone at this power level will have traction problems unless they are on et street's or legitimate drag slicks. i would much rather have the ls7 heads then the trick flow heads because 1,300+ dollars would be better spent on good tires which would help my ET's or help my speed on a road course more then the trick flow heads any day of the week. i agree they add more power under the curve.... but at what expense???

 

Thanks for the result and efforts.
Both heads are amazing.



This off topic Sorry but no way in hell N/A 347CI Will make
495rwtq

 

Actually the prices for the heads are pretty comparable. ~$2500 for each with a slight edge to the TFS because you will need to change the springs on the ls7 head.

Manifold is where you save the money.