You guys honestly believe that no timing or fuel adjustments for the other heads is a fair comparison???

This is not bashing anything but the test precedure.

A different pair of heads is VERY likely to want different timing and fuel, that is reality not opinion.

 

Any links to this so we can keep up with the results?

 

http://www.corvette-guru.com/modules...d=7225&forum=1

 

My AFR heads set the N/A top speed at the 2009 LTX Shoot-Out, 126.9 MPH! While 96capricemgr basically says AFRs ain't squat, who do you believe? I don't recall him being at any major LTX events, or setting any records!

WD

 

I would say AFR and TFS are neck and neck now days. As others have mentioned they are great casting and once a good ported gets his hands on them you should be happy.

But for most builds you dont really need aftermarket castings. AI/LE can get a stockers flowing lots of air, research the results.

 

I think AFR's new Eliminator heads are the best bar none.
I run the older style AFR 227 LT4's and will be upgrading to the new style Eliminators soon.

From street setups to full out racing setups AFR heads are a great choice. Not saying stock ported heads or TrickFlows are no good but the OP asked about AFR's.

Tony Shepherd

 

Thanks for the link buddy. Rick

 

I said the test was biased and invalid.

I have attended a large national event, those who did not like the result simply made excuses for why my car ran better(ET and MPH) than the others it was put up against. Was the second fastest NA qualifier at the event, the fastest being another AI headed car. There were trailer queen strokers there and a 350ci that drove 500 miles to be there ran faster .

 

A different pair of heads is also VERY likely to want a different cam as well - we do have our cams ground off of heads flow numbers don't we?. Therefore to be fair should all the heads have their own custom ground cams for them as well??? Too many different ways to look at it...is it considered fair for a head that stalls at .5 lift to be ran against a head that flows up to .650 using a .600" cam in both engines? Using similar logic I can argue that the test was unfair against the AFR heads for using such a tiny cam. The baby cam used was not fair at all, AFRs want a lot more lift and duration!!!

We could run a stock cam and they would all perform extremely similar making the AFRs look like a waste of money, or pick a huge .7XX" solid roller and spin to 7,500rpm and exaggerate the differences even more. You have to draw the line somewhere in a comparison. Your argument is not an incorrect examination and could be considered true to a point, it just sounds like nit-picking.

 

What if someone tested LE and AI heads and did not retune in between?

Seems to me we have seen that test WITH retuning and even when the "losing" set had ported intake many wanted to say the test was invalid. Yes there was a cam swap too but a couple degrees and similar lift, vs a ported intake call that a wash.

IMO the "matching cams to heads" thing is grossly overstated, the valve spends so little time at peak lift anyway.

Far as the tuning they could have stated they tested all motors at 34-36-38 degrees and used the highest result for the comparison and tuned all to one air fuel ratio not a half point spread. That would have taken a LOT less time than the head swaps.

I wonfder why all the other head's info was cut off at a much lower rpm? Maybe part of the low numbers was only the AFR head had enough spring/light valves to control the aggressive XFI lobes?? Taking the graph more than one data point after peak would have let us see more.

 

I am amazed people are getting so passionate about this

Anyway, the only fair way to do a "head-to-head" comparison is with the same cam, valvetrain, etc. Of course, each should be optimized in terms of tuning. Otherwise, you are introducing another variable. If head X is supposed to work better with a certain cam and so is head y, do a paired test of each head against the other using both cams in each. But that really would not be likely to change the results. Anyway, as I posted earlier, if you are talking about modified heads you are comparing porters, not castings. You would need to know from them which they prefer and why. The great thing (for the sportsman race/street enthusiast) about modern casting and CNC machining is that you really don't need a head porter! Unless you are restricted to stock castings, you can buy "as cast" heads that are ready to use and are pretty damn good and you can get them factory CNC machined to a state where they are better than most porters can do for less $$$.

High level racing and classes that require you start with a stock casting will still need hand work, sometimes a lot of it. But most people would be better off getting the right head in the first place. As to which ready to go head is better, the information could be easily obtained but would anyone believe it?

Rich