Hey Guys...

Seems I have continuously gotten flack in the past for questioning some of the larger flow numbers that casually get thrown around the internet. At times I have advised getting them independently flow tested, even offered to test a few etc., and usually end up getting bashed for being "negative" or worse. Perhaps if any of you had the chance to walk a mile in my shoes you might understand why I question the results and why you should to. First off, this information isn't aimed at anyone or any shop for that matter, nor are we "above the law"....feel free to double check our advertised figures as well. The information I have compiled for you is basically the bulk of the larger factory ported LS heads I have had the opportunity to flowtest on AFR's equipment over the last 12-18 months. For that matter, some of the information you will see might have been from the very set of heads a few of you sent in for us to flowtest for you. No names will be mentioned so don't ask, but you better believe that a lot of these heads had much sexier #'s on paper (advertised)....Take this info for what it's worth, throw it in the garbage, call it BS, or possibly have an open mind and pick up something that might help you down the road.

While big flow numbers are certainly more attainable with larger volume ports, getting those kinds of numbers still doesn't come easily....especially in a "production" environment. Any highly competent cylinder head shop can certainly produce good or great results on a pair of heads they invested 50-100 hours into, but is the average Joe actually receiving a comparable set of heads with the same results for a few thousand dollars? Maybe...maybe not

Here is a compilation of some of the larger stuff I have personally flowtested and documented....I didn't bother with the smaller and medium sized stuff I have seen because most of those numbers weren't even in the hunt. Of course I have not had the opportunity to test and flow everyone’s product and a claim like that would be ridiculous, but I have seen quite a few and the flow chart below covers the BEST of what I have seen come across our flow equipment. Keep in mind guys, this IS an “apples to apples” situation, as all of these cylinder heads were flowtested on the exact same equipment with the exact same fixtures, radius plates, flow tube, etc.

For all of the guys that like to crunch numbers, this information should keep you busy for awhile.


All numbers recorded utilizing 4.125 bore unless otherwise noted.

“T” indicates turbulent and could not record any data

“Stg 3” heads were heads that I knew were advertised as such. Others might have been “Stg. 3” but I only labeled heads I was sure of.

INTAKE FLOW

Head…………Int. Valvelift…………………..........Runner
…..….200….300….400….500….550….600…….Volume…………Comm ents……….

“A”….136….199….257….294….305….313………232 cc’s
“B”….134….195….239….267….280….289………229 cc’s
“C”….131….189….240….275….287….282………221 cc’s…(LS1 castings)
“D”….141….206….259….291….303….313………231 cc’s
“E”….145….203….253….295….309….321………246 cc’s….Stg 3
“F”….141….206….263….300….315….332………245 cc’c….Stg 3
“G”….135….201….260….304….316….”T”………239 cc’s……Stg 3
“H”….140….211….260….285….286….287………243 cc’s……Weak for size
“I”…..137….207….252….290….306….318………242 cc’s……Stg 3
“J”.….126….186….231….263….277….290………228 cc’s
“K”….121….190….246….278….293….306………230 cc’s
“L”….146….208….264….301….314….323………237 cc’s.Stg.3 (good overall)
“M”…137….207….252….290….306….318………242 cc’s……Stg 3
“N”….136….190….249….288….301….312………241 cc’s……Stg. 3
"O"...147....213...264...300....308...304..... .249 cc's.....Stg. 3
"P"....144...205...259....299....316...330......24 9 cc's....Stg. 3
"Q"....129...200...258...295....305...308..... .232 cc's
"R"....135...200...251....293....311...317......25 4 cc's....Stg3 (BIG!)
"S"....148...200...247....289....301...304......23 1 cc's...LS6 head w/ 2.02
"T"....132...195...240....283....296... "T"......227 cc's...LS1 head w/ 2.02
"U"....136...194...248....267....275...281......23 4 cc's....5.3 head/weak #'s
"V"....128...186...238....274....287...293......23 1 cc's
"W"...141...206...256....299....315...324..... .236 cc's ...LS6 Casting/Good#'s
"X"....143...207...265....298....313...."T'......2 40 cc's....Ported 6.0 Casting
"Y"....136...197...242....281....294....293.....23 0 cc's...Stg 3 (soft #'s)
"Z"....137...211...270....310....324....336.....240 cc's ..New "Best" peak #'s
"a"....138...205...259....295....304....309.....25 4 cc's ..CNC Ported Dart/BIG
"b"....160...240...305....342....N/A....368.....275 cc's ..."b" for BAD AZZZZ!
"c"....141...214...267....303....306....311.....21 5 cc's....Very good #'s (11')
"d"....138...215...264....304....317...."T"......2 29 cc's....Rolled Valve (13.5')
"e"....158...228...279....315....324....331.....230 cc's....Huge area under curve
"f"....161...225...272....312....321....323.....240 cc's....Very solid #'s!
"g"...159...228...281....314....324....330.....230 cc's....Ported AFR 225's
"h"....142...202...260....303....316....323.....24 9 cc's....Hand ported 205 casting

AVG..137….200….252…..289….302….308....…237 cc’s

AirFlow Research #’s
205….145….210….257….290….301….308………205 cc’s...(205 w/ 4.125 #’s)
225….151….221….270….306….315….322………229 cc’s


EXHAUST FLOW w/ 1.875 pipe (curved to simulate header)

Head………….Exhaust Valvelift…………………..Runner
……...200….300….400….500….600............Volum e

“A”….113….150….180….208….230…………….84 cc’s
“B”….107….147….196….218….228…………….85 cc’s
“C”….107….153….184….205….217…………….82 cc’s
“D”….112….165….195….215….228…………….86 cc’s
“E”….111….156….202….235….246………...…88 cc’s
“F”….126….170….204….226….236…………….85 cc’s
“G”…117….164….201….229….242………………87 cc’s
“H”…113….156….189….221….231………………85 cc’s
“I”….114….145….179….211….237………………87 cc’s
“J”…..97….133….166….193….213………………89 cc’s……Very weak for size
“K”….117…157….194….218….228………………83 cc’s
“L”….114….155….214….238….252……………..90 cc’s……Big, but good #’s
“M”…120….177….219….240….251……………..87 cc’s….....good #’s
“N”….105….144….177….208….222……………..89 cc’s……Very weak for size
"O"....115...166...202...228...241............ .88 cc's
"P"....116...163....211...236...241........... .84 cc's
"Q"....109...156....208...224...227........... .89 cc's.....Weak for it's size
"R"....113....156...195...227...241........... .91 cc's......(BIG!)
"S"....108....146...188...226...235........... .84 cc's....Soft low/midlift #'s
"T"....120....171...200...217...224........... .84 cc's...1.570 vlv, good low#'s
"U"....111....147...189...209...224........... .84 cc's
"V"....111....144...168...186...194........... .86 cc's....VERY weak Exh #'s
"W"...126....177...215...230...241............ 82 cc's.....Good #'s
"X"....115....150...177...194...208........... .89 cc's....Very weak for size
"Y"....119....160...182...195...200............83. 5 cc's..Small port/Very soft #s
"Z"....117....170...215...241...253........... .95 cc's.....BIG port / strong #'s
"a"....114....153...193...220...233........... .90 cc's.....BIG port / avg. #'s
"b"....120....176...205...221...230........... .86 cc's.....Needs MORE!
"c"....118....164...207...232...245........... .96 cc's.....Good numbers / BIG
"d"....110....174...213...231...240........... .84 cc's.....Good #'s
"e"....128....184...228...245...253............85 cc's.....Big numbers everywhere
"f".....124....164...203...226...235.......... ..84 cc's
"g"....131....179..230...249...255............85 cc's.....Ported AFR 225's
"h".....119....160...189...213...227.......... .?? cc's.....Weak considering intake flow/size

AVG...113….157….194….219….230…………….86 cc’s

AirFlow Research #’s
205….118….171….206….226….240……………..84 cc’s
225….120….180….220….241….250……………..85 cc’s


What's interesting to note is how well the AFR 205's faired among a group of cylinder heads that have a huge advantage in port volume. It becomes a little clearer why the 205 has consistently put up good numbers on the dyno and great results on the street.

Hope you guys enjoyed the data....It represents quite a bit of time invested.

Regards,
Tony Mamo

 

GREAT INFO! For you home head porters out there here are mine on the same bench:
intake 218cc exhaust 82cc 3.900 fixture/1 7/8" pipe
.200 136 / 114
.300 198 / 144
.400 246 / 179
.500 261 / 208
.600 272 / 222
This is a 806 casting perimeter bolt head with production valves.

 

All I can say is there are a lot of "happy" benches out there. I commend Tony for posting good hard comparative data. This could have been an ugly thread by posting names, but I think its been done in a fair and reasonable manner so as to educate, and not inflame other vendors and porters out there.

This test has been a long time in coming. Many of us have wanted to do a head shootout, now its been done for you. I'm sure some of you can fill in some of the blanks on whose heads are in there.

The imporatnt thing to recognize though is how important it is to verify heads, and how marketing has forced vendors to inflate numbers in some cases.

The other thing it illustrates is that even small variances in production can affect a set of hand ported heads that unless you check can kill flow...

Props to Tony on all his hard work...

 

Tony, are all of these LS6 type heads except AFRs and "c"? Also, you said 4.125 fixture unless otherwise noted- there are none noted except AFR 205s intake #s. Did you mean 3.900 fixture unless otherwise noted?

 

Yes Bo...that is correct.

They are all LS6 or LS6 "style" heads except for "C" as you noted.

Regarding the bore fixture, ALL of the heads were flowed on the big bore. I probably made it more complicated than it needed to be. I just wanted to address the fact that the 205's have higher numbers than we advertise because we advertise it utilizing the smaller 3.900 bore.

 

Tony, thanks for posting those flow #'s

 

Great post. I would like to know what brand each letter represents though. Could you perhaps PM me the info?

 

I can't go there guys....I'm trying to keep this as professional as possible while still providing you with some very powerful information. Hopefully this post is an eye opener and perhaps give some of you a different perspective. Also, it sheds some light on why it's not so easy for me to swallow and just "accept" some of the higher figures thrown around these boards when my own personal experience certainly teaches me otherwise and leads me to be skeptical at the very least.

 

Good info. It would be interesting to see how the C5R stacked up in that group.

 

Good info, thanks.

 

thanks for posting the info.how about some flow # on a 3.9" bore?(yeah,i'm a pain in the ***)

 

Lets add a little math to this:
INTAKE
head - average #s - average #s per cc
A - 250.67 - 1.0804
B - 234 - 1.0218
C - 234 - 1.0588
D - 251.17 - 1.0916
E - 254.33 - 1.0339
F - 259.5 - 1.0592
G - 243.2 - 1.0176
H - 244.8 - 1.0075
I - 251.67 - 1.0399
J - 228.8 - 1.0036
K - 239 - 1.0391
L - 259.3 - 1.0942
M - 251.67 - 1.0399
N - 246 - 1.0207
Mine222.6 - 1.0211 (3.900 fixture)
205 251.83 - 1.2284
225 264.17 - 1.1535

EXHAUST
A - 176.2 - 2.0976
B - 179.2 - 2.1082
C - 173.2 - 2.1122
D - 183 - 2.1279
E - 190 - 2.1591
F - 192.4 - 2.2635
G - 190.6 - 2.1908
H - 182 - 2.1412
I - 177.2 - 2.0368
J - 160.4 - 1.8022
K - 182.8 - 2.2024
L - 201.4 - 2.2378
M - 201.4 - 2.3149
N - 171.2 - 1.9236
Mine173.4 - 2.1146 (3.900 fixture)
205 192.2 - 2.2881
225 202.2 - 2.3788
Average #s are just that, average #s per cc is my way of seeing how effiecient that port is.

 

tis a damn shame when my set of cnc'd and hand ported heads flow just as much as your home ported ones.

224.5cc int / 83.7cc exh




as always good stuff Tony, should keep me busy for hours

 

Mine are also with the production 2.00car/1.55truck valves

 

yeah,tell me about it good work Bo.next time i need some porting done i'll give you a call.

 

Great post Tony.
I figured this was coming at sometime.
I have flow tested 5 sets now myself and not 1 have hit the advertised numbers.
Absolute Speed's were within 5% almost everywhere, and the LPE heads were within 3% everywhere.
Some other vendors wern't within 15% anywhere. (Talk about being pissed)

 

I also have seen a thread somewere were a guy flowed a set of LS1 castings that supposed to go 32x @ .600 and only went 28x on an independant bench of the same type. I would rather low ball my stuff than inflate it. I would love to have an e-mail from a guy that flowed a set of heads he got from me complaining about them flowing more than I sayed they would; "Man, Im sorry 'bout that "

 

this is very interesting. we can kinda see which heads are which from the runner size. in any case, at least all these heads are flowing more than a stock set of ls6 heads. also, i think people worry about peak flow numbers, when those arent as important as the numbers below it. peak is only attained at one moment in time, whil flows at .100, .200, .300, .400, and .500" are attained twice during a reveolution.

 

^^^^^

 

Great post Tony,
I am sure the heads Mr. Norris ordered thru you for me will flow like that.