Suprise! Youre missing the point. I see the joke about the hot cam but the issue is....

If head and cam combos need to be specifically tailored to work together, as you have stated so many times, then don't you want the head manufacturer to pick your cam for you? Im asking sincerely.

Then doesn't it come down to brand preference of the head? Truly at the end of the day what is the hp deviation of an optimized head/cam on similar ci?

I do agree with you about the percieved "cool" factor.

 

I saw my name mentioned.... thus, as I had posted a month or two ago, it was me that went from ported Dart cylinder heads to AFR non-ported heads and went significantly faster with the AFR cylinder heads on my 383/SR/219 combination. (I am not sure what Corky has seen in et gains with AFR's)

The one thing that you simply cannot deny, AFR cylinder heads work on "our" applications, which for the vast majority of us is 350-434 sbc that are typically street/strip applications meaning, we are looking for power off-idle up to somewhere around 6500 rpm..... and with this, I personally have not seen any other cylinder head brand outperform an AFR cylinder head..... it is simply as that to me. I never listen to marketing, I do not have a single clue what any cylinder head manufacturer preaches in their advertisements, I don't read them. I simply know, that over the last dozen years on this forum there have been one hell of a lot of racers, some very, very sharp people who have put the AFR's cylinder heads on their engines and then went out and run an impressive et. Thats enough for me..... and somebody could march an army of fluid and shock engineers in here to tell me different, it wouldn't work..... the AFR's made my corvette faster as they did for many others.... which is all I was after.

Jsup, my only comment on everything you have posted, is that "in my opinion", cylinder head flow is not a parameter of a good cylinder head, but it is instead the result..... a good efficient chamber with a well tuned runner will create a good flowing cylinder head in my opinion. This might be best seen by every single cylinder head porter in the country..... as you know, they will get a cylinder head, start massaging the runner, then test on the "flow bench", then work over the chamber.... then test on the "flow bench", and then repeat until they believe they have a good performing cylinder head..... what they are doing is quantifying their results by seeing how much airflow they have created....... this just might make airflow kind of important ? Is there another test I am not aware of they do when trying to improve a cylinder head ?

We have to ask ourselves, why is the flow bench "the" testing tool for success by 99% of the professionals who design and/or port performance cylinder heads ? Could it be, that the "flow bench" shows us the result of a good cylinder head ?

My parting advise to all forum members trying to decide on which cylinder head to run..... buy the best flowing cylinder head you can afford with your budget with a moderate runner size..... all of this other talk, maybe Grumpy & WJ have to worry about it.... but we don't, we're driving street cars.

I recommend AFR's......

 

I wish people would debate cylinder heads in every thread!

 

It's getting real old, I give up even asking questions when it comes to cylinder heads.

 

Hey guys, this is exactly what I am talking about.

How about you go read this:
http://forums.corvetteforum.com/show....php?t=2158188

And answer in that thread.

Also, as I said a few posts ago, your anecdotal evidence has no value. GO back a few thread, read the lengthy posts I put with scientific backing, then we discuss intelligently.

From page 4:

The fact someone goes from old technology worn heads and a car that needs a tune, to new heads, gaskets, rockers, valves, etc...and picks up speed, does not tell me anything about the heads chosen only that new heads for the fact they are new and have the car tweaked will run faster. Again, says nothing about the choice of head.

Thank you.

 

Nothing, that's my whole point. It should ALL be treated skeptically. Not taken as science and repeated.

 

AFR makes a wonderful, top quality product, yes.

There is nothing wrong with listening to the designer. But back to my fuel injector example, you listen to Lucas and the disk guys, you listen to Bosh and the pintle guys, and YOU come to a decision.
....
What many people do is say something along the lines of "I'm not telling you what kind of head you should buy, but it should have an A engraved in the front, and an R, with any letter you want in the middle".

My point is exactly that. People read a brochure and say "this is what you should look for in a head".....and go on to cite brochures.

Again, the basis of your post has nothing to do with the basis of mine.

Let me repeat, my gripe is with people passing out bull**** information as fact, when it is straight out of the brochure of a particular manufacturer.

 

Well, that's up to the reader I guess

YEP....I agree. No argument from me on that. ANd what being right to me means demonstrating the bull**** that passes as fact here. If I can do that, I win..
No problem. I am not saying Deakins is a head god. On paper, he knows his stuff and does this stuff to pay his bills. I have three other engineers I confer with to validate what Deakins and anyone else tells me. I only post those items which all 4 engineers agree is accurate. Look, 2+2 is ALWAYS four. I don't see why it's an argument.

Yes, you are. Thanks for that.

 

This is what you are talking about ? I do not understand.

I have already read the other thread Jsup, or at least as much as I could get through in my limited time.

So, what you are saying is that my "anecdotal evidence" has no value ? In otherwords, me going faster with one cylinder head vs another did not really happen and/or does not matter because you have created a very long post on another thread ? I really do not understand.....

I do know, you have said flow bench results are not important..... and yet, right this minute as we speak, cylinder head professionals all around the world are testing the cylinder heads they just ported on a flow bench...... to put it as bluntly as I can, people pay a chunk of change to cylinder head porters, they port the heads for additional "air flow".... they then give the cylinder heads back to the person who paid to have them ported, who then put the cylinder heads back on their motor and they now make more power and go faster..... in otherwords, increasing the flow of your cylinder heads results in more power and faster et's...... plain and simple.... there is absolutely no way in the world a person can swing it any other way..... a person gets his heads ported, puts them back on his car, it now makes 20, 30, 40 and in some cases even 50+ more HP than it did before..... and it now goes faster.... which I might add, is the goal. The above is not guess work, nor is it an opinion, it is simply a fact and the above has been happening for several decades......

This makes cylinder head airflow very, very, very important..... no getting around it, just isn't..... swing it anyway you want, just can't get around it...... you might want to consider editing your previous comments.

Which all of this brings us to "your" quest, which is to disprove the importance of cylinder head airflow..... as we all know, the "sole" reason for your quest is: Ricky told you either in a thread or PM, I do not even know which, that you were leaving power on the table because you were planning on purchasing cylinder heads that do not flow as well as AFR...... this angered you, and you were quite verbal about being angered by this in various threads, especially because it was quite obvious that the AFR's really did flow more than the Darts.... in fact substantially.

Therefore, you have gone on a quest to prove to us all that posted cylinder head manufacturers flow numbers are not important...... which is fine by me. I never told you were leaving power on the table.... and it wouldn't bother me if somebody told me the same, in fact I am leaving power on the table with my cam, compression and cylinder head choice..... but thats okay.

The problem is, airflow is very, very, very important...... by increasing airflow without drastic changes in the runner will increase your HP potential..... always. And this is seen by the ritual of thousands of people either porting their existing cylinder heads or puchasing aftermarket cylinder heads that "flow more"..... these gains in airflow then make them more power. Their proof of this is on the dyno and at the track..... you can't get around it, you just can't.

 

What bull**** ? What myths have you disspelled ?

 

This is not about heads, we are not debating heads. Period.

What I am talking about is the facts vs. the myths and how these relate to what should be quantified into how you make your decision.

This is an exercise of consumer empowerment. Period. It has nothing to do with heads.

It is unfortunate that if you had very specific technical questions that you can feel you can ask them.

This is why I formatted this is such a way to be cut and dry science.

I want the forum to be a place where people can ask honest questions and be given honest answers. And not abused for doing it.

 

Did you read the link? It's six long posts. Go read it.

To answer.....ALL OF THEM!!!!

 

Okay...well, I took this out of your link specifically...

So you'll listen to the people that design on wet-flow benches and take their word for it because to you "it makes sense". Your contradicting yourself here, you said you shouldn't listen to the people that DESIGN the products as they are just MARKETING themselves! So which is it?

 

Well BeachBum I can see that you are the standard consumer that, for a long time has been told by someone (often with little education on anything other than putting engines together) that the best way to modify your existing heads is to suck air through them, and then grind away at them... Then they will suck more air through them and justify their very large bill. Since you seem very comfortable with leaving out 95% of what actually happens inside the intake tract during operation, my guess is you will be loving your head guy for years to come. Let’s just say there's a reason he doesn't work on the cylinder heads that go on an F1 car, or any of the other applications that have moved beyond the practice of grinding and testing, grinding and testing, and simply wasting casting after casting. Also, if you feel that all of the guys that port heads for serious efforts are just looking at the flow bench outcome you are sorely mistaken. In most cases they use the flow bench simply because it’s the only thing that they can afford to use; price a cutting edge wet flow set up (and that isn’t even the be all end all unit). Better yet, see how much it costs to have an engineer that models and runs CFD code on all you designs; then have another one evaluate and make changes when looking at the output. That’s the way heads are designed when the funds are there to support it. The reason being this, the only way to produce the optimized results is to look at as many variables as possible when designing the port. If you dry flow bench you look at one; the restriction. If you have the choice to look at none or one, one is better but that does not mean we shouldn't even attempt to look any further.

Frankly, I'm not surprised in the least at what I hear out of you; I hear it more days than not and you get used to it. There is currently a fundamental change going on in motorsports; the days of guys that had little education, or training in the academic side of mechanical and aerospace engineering being a top engine builder are slowly sliding away. Why do you think that NASCAR cup engines had a big transition in the mid-late 80's? They started letting the engineers put their abilities to work on their engines (because the money started flowing), the result. Connecting rods are now piston guided, profiled down to reduce to minimum amount of mass while still holding together, crankshafts are profiled and lightened exactly where they need to be to maximize output, rocker ratios are consistently in the 1.8-1.9 range... the list goes on and on. Many things that most people are not even aware of have been being done by this new generation of engine designers for the past 10-15 years. The cylinder heads of an F1 engine are NOT designed on a dry flow bench (a big change from your thinking) as there are better ways to approach the optimization process. Do you realize that several commuter aircraft that you may have ridden in, flew their first flights having never been in a wind tunnel for testing? We are at that level of technology; sadly, like the professional I learned from so many years ago, a generation of performance engine builders are slowly being phased out.

BeachBum if you like AFR so much that's great; if they work well for your application that's even better; you made the right choice. The fact remains that how and why this head works the best in your application is lost to you. If you understood why, maybe you could build a higher end engine (and compete in a class governed by strict engine rules), one where you simply can not copy what someone else has done. That's the big trick isn't it? How do you go about making more power out of an engine than someone else that has the same money as you do, to choose the same parts as you do? If you don't understand these concepts you have little hope of beating the other efforts. In my case, most of my engines win or are at least very competitive; I attribute that to the knowledge I have obtained, not the parts magically working better for me than the competition... If you don't want to bring your game up a few levels you can simply stop reading and responding to this thread. The purpose here as I can tell, is to attempt to get some good information out that isn't reported on in Corvette Fever or Chevy High Performance. Higher level technical aspects that generally don't leave the shop floor are something that people should want to read; unless of course you don't like winning.

 

Wow...you are so much better than the rest of us Im not sure why anyone as intelligent and enlightened as you even bothers reading much less posting on a forum site full of uneducated people. We are so beneath you.

What shop or whose race team do you work ?

 

You are # 2 that has said this in 2 days. This shouldnt happen...

Auroras post was spot on. We get your point about people looking around Jsup.... but boogering up every thread endlessly-Not taking a poke at ya but I dont see anyone else really making that big a deal out of it. Let the Rick thing go
As far as Im concerned if I thought Kmart made something better Id recommed them.
Different strokes...

 

Huh ??

When I need an F1 engine, I'll call you....

btw, as a note, I am a degreed engineer and nationally known in my chosen profession of CNC technology..... I have trained the engineers who train the engineers in Aerospace, Automotive, Energy, P&W and Metalworking marketplace. I have written multiple nationally published technical articles and been sought, interviewed and quoted by "every" Machine Tool Publication in North America. My point, I understand technology as well as anybody you have ever met.

And lastly, lets forget about all of this garbage talk..... cut to the chase, for the following application, in your opinion, who's cylinder head is best for the application.... please include the part number. And why ?

383 street/strip application
6500 rpm max operation
$ 2000 max budget
Hydraullic roller cam 232/232 @ .050" .575 lift

In otherwords, the average corvette forum member in a C4, he upgrades to a 383, drives his car on the street, but races it on the weekends at the local dragstrip on the weekends..... who do you like and why ?

 

But can you design shock absorbers?? If not I don't want to know what you think about cylinder head design.

Sorry I had to do it...it's all in good fun.

 

This has gone on long enough. It was closed at one time due to the hostility, reopened, and now closed for good.

To the original poster: I hope you understand and have gotten the answers to your question.