Bill's 02 Z-28 SS

Hi Tony
You wrote "Two more quick things....during our SuperFlow Engine Dyno testing mentioned earlier, we also had the opportunity to test a popular Stg 2 factory ported cylinder head that we secretly purchased brand new specifically for this test."

When you are talking about the Stage 2 factory ported cylinder heads, can offer some additional information. If it is the Factory ported LS6 heads (GM), the CC is 61cc which would have given you a CR of 11.2:1. Your statement is a little confusing - it implies a purchased factory head from the factory or was it a third party porting job?
Thanks

Bill

DrkPhx

iTrader: (15)

Are the AFR 225 62cc chamber heads just 72 cc heads milled or are they a different casting?

PewterZ28

iTrader: (1)

I believe in another thread I read they were a different casting. Someone please correct me if I'm wrong.

Also, I posted this in the other topic but wanted to post it in this thread also in case someone in the future is performing a search.

I just got off the phone with Tony. Just in case anyone is also wanting to stay with the stock cubes for now but increase the displacement in the future, here's what Tony said... (good info for anyone making a search in the future):

The 62cc 225's can be milled 0.018"~0.020" to get you to 59cc. Then with some flat top fly cut pistons and a Cometic gasket 0.040" thick, the compession ratio would be 11.27:1.

If/When you want to increase displacement you would have to get some dish shaped pistons to bring the compression ratio back down to the 11.2~11.5:1 range. He also said something about having part of the pistons flat because of quench but I don't think I wrote that part down correctly.

Once again, thanks Tony!

wallstAL

Tony Mamo @ AFR

iTrader: (13)

Always lurking Al.....That is your favorite "icon"!


As far as the 62 cc version of our 225 head, it is the same casting as the large chamber version AND the 205 for that matter (all of our LS line of cylinder heads start with a casting that is some 180 cc's or so and meant to be CNC ported to the various programs we offer). The smaller chamber 62 cc version of our 225 is not simply a 72 cc version milled down....it does have a different chamber design than it's larger brother. By the way, unlike our 205, both of the AFR 225 offerings (62 & 72 cc) require the use of a "large bore" gasket with a minimum of a 4.125 opening (a 1041 Felpro for instance is 4.135) even when used in conjunction with a factory shortblock and a "3.900-ish" bore.


As far as your questions regarding the dyno test and the "factory ported" Stg 2 heads, I simply meant that they were "factory" LS6 castings ported by sponsor "anonomys" designated to be a "Stg 2" port job (and were suppose to flow well over 300 CFM).


Tony M.

DrkPhx

iTrader: (15)

Thanks for clearing that up Tony. Does Cometic make a head gasket with that bore and does the bigger bore size on the gasket change the compression ratio any?

Mirek

Tony thanks for continued contribution. Those heads and every aspect of them have come under a tremendous amount of scrutiny due to the fantastic results reported. You do an admirable job of promoting the facts and not loosing your temper. This reminds me of the LGM/Kooks header wars except their aren't even any "Kooks" in this case.....but I digress, the retainers are titanium (per the web-site) can you provide some specifics on the valve material and their weight for the 205's?

I almost have enough cash to place my order, I cannot wait to throw 'em on.

RAGE OR DIE

LS123

iTrader: (11)

Need I say more..........................

BoneSS

iTrader: (9)

Tony,

Thanks for the great info. Will the cam you bring out in your Vette be in the 230/600+ range?

destroyerSS

iTrader: (2)

With your test of a stage 2 head, What valve's and what else did they do to the heads?? and was this a test of a "LS6 style head" or a real LS6 head and what was the cost?? Not trying to bash but if you beat $ 1300.00 head big deal! Or was it a high end shops porting. Thanks

mjf454

Does it really matter? Out of the box the AFR head is better than a LS1 or LS6 head. Isn't that what everybody has wanted for years? Buy them as cast and have your favorite head porter go to town with them, they will be better than a ported stock casting. Why is everyone complaining about the fact we now have a better head to start with? If people have buyers remorse about buying a ported head that has less potential than a AFR head, I would suggest not modifying your motor for about 20 years. That way you will take advantage of 20 years of worth of development. I am happy to take my ported heads off and replace them with the AFR 225's. Do I feel screwed? Hell no. I am glad there are more choices now.

destroyerSS

iTrader: (2)

Thanks for the reply but I WAS NOT ASKING YOU!!! Like i stated in no way am i trying to bash. I was simply asking a ? about the kind of heads they used!! I think it great that there is more options availible as well. But when a company make a statement about HP claims i would like to know all the FACTS!!!! Because from on head porter to another you can probably see big gains or lose's. And as far as the AFR head being a better head out of the box i would sure as hell hope it is cause there is quite a bit of price difference

redc4

iTrader: (2)

Can someone please tell me how much the cfm gain is over a stock head on the same bench? Surely AFR knows the answer to this???

Tony Mamo @ AFR

iTrader: (13)

RELAX.....Use the telephone if you need "immediate" answers.

AFR 205's are 70-75 CFM more than a stock LS1

...................45-50 CFM more than a stock LS6 (while being 6 cc's smaller)

Gains increase another 20 to the above figures if comparing stock heads to an AFR 225.


By the way, I was referring to intake ports above.

Stock LS1 and LS6 heads are very close to one another on the exhaust side and flow around 190 CFM (with a pipe). An AFR 205 goes around 235 CFM (@ .600) and an AFR 225 goes around 250 CFM (also at .600).

The same 1.875 pipe was used on all the figures above.

You could also try PM'ing me if you need information I might have omitted answering in any of these threads....It would be near impossible to answer every single question and I try to respond and give input on topics not already gone over. I'm sure if you searched thru my posts I have already touched bases on the gains seen on our flow equipment when comparing AFR heads to out of the box "stockers".

Thanks,
Tony

Tony Mamo @ AFR

iTrader: (13)

It was a head that retailed for around $2000 at the time and I believe the head came equipped with 2.02 aftermarket intake valves and 1.57 exhausts (could have been 1.600...I could check if its "important"). It was not an LS1 head to answer your question, whether it was an actual LS6 head or an LS6 "style" head I also don't remember, but I know for a fact it LOOKED like an LS6 head, not the more narrow LS1 design. This head was not obtained from an "obscure" vendor, trust me on that, and it wasn't a "fluff and buff" cheapy either. Highly likely that quite a few of you guys that read this board are running exactly what we tested and thats all I care to say about it. We purchased and brought them to the dyno with us to truly see where we would stack up against a piece that "fairly" represented what was commonly available at the time....that was the information we were seeking. Were we better, and if so, exactly how much??

The gains we saw and the difference in the overall power "curve" were "inline" with the flow results/versus port volumes and exactly what we were hoping for. The AFR piece just proved to be a more "efficient" cylinder head.

Lastly guys, we never claimed that the 205's were going to "blow the roof" off of a GOOD factory ported cylinder head (it might when compared to an "average" or poor example), but we were hoping for it to be BETTER than a "good" piece regarding peak power output, and add alot to the other aspects of the power curve as well....that being low speed torque and drivability, and the ability to improve fuel economy and overall "efficiency". That being said, I feel confident that the 205 program has hit the mark....Now we will see if the 225 can up the ante a little bit more and hopefully spread the "gap" a little farther.

Tony M.

Bo White

iTrader: (59)

Great work and info Tony, Thanx.

gollum

iTrader: (1)

Does anybody have any info on the new GM factory ported heads soon to be release on the 2006 ZO6 427 CORVETTE (500 hp). Is it a ported LS7 casting or a newly designed casting? What is the intake port volume?

NLang

iTrader: (12)

AFR tech thread bud

redc4

iTrader: (2)

Tony, thanks for your reply. Clears up a few things for me.

cyphur

iTrader: (10)

NoseUp, he didn't read the title apparently.

Tony, thanks for all the info, I will continue to keep reading these as my head decision grows closer. You by far are one of the most informative vendors on the board, and I always look forward to reading your threads. Keep up the incredible work!!