http://www.chevytalk.org/fusionbb/showpost.php?pid/1554463/


[QUOTE]ALUMINUM HEADS: T&L Engines; DART PRO 1 Platinum 200cc, American Speed; AFR Eliminator Street Head 180cc, Trick Flow; TrickFlow Super 23 Street Head 195cc, in other words all the latest generation available from these head manufactors.
Where noted by the builders I have noted any variances in the builds (all other variables were the same).
ENGINE:The basic motor is a SBC 383 stroker 4 bolt main with 4.03 bore and 3.75 stroke. T&L used 6.0” rods where all others used 5.7” rods.
CAM: Cam is the same Comp Xtreme Roller XR282HR 230/236 duration @.05, lift is .510/.520 using 1.5 ratio rockers and only T&L used 1.6 ratio rocker yielding .544/.555 lift.
CR: Both T&L and Trick Flow reported using 10.1:1 CR and American Speed reported using 9.5:1 CR
CARB: Everyone used the same Holley 750 CFM carb.
INTAKE: T&L and American Speed used the Edelbrock Performer RPM intake Trick Flow used the Victor JR.
IGNITION: MSD 6AL, timing was 36 degree
HEADERS: 1.75 Primary tubes
VALVE SIZES: 2.02/1.60
COMBUSTION CHAMBERS: DART PRO 1 Platinum; 72cc, AFR Eliminator Street Head; 75cc, Trick Flow Super 23 Street Head; 64cc
DYNO RESULTS:
DART PRO 1 Platinum 200cc; HP440/465TQ
AFR 180cc; HP491/501TQ
Trick Flow 195cc; 460HP/451TQ
Note: The only Dyno results on the AFR 195cc heads I found was American Speed using the Comp Xtreme XR288HR which is 236/242 duration @ .05 and 520/540 @1.5 ratio and the results were 503HP/517TQ

I find it difficult to believe there was such a difference in performance from brand to brand especially the numbers reported using the AFR heads.
This is especially confusing considering that T&L chose to use 1.6 ratio rockers increasing the lift from .510/.520 to .544/.555 and the AFR 180’s gave up 20cc in intake runner along with only having a CR of 9.5:1 vs 10.1:1 for what ever that is worth, certianly not an advantage.
Could it be that the AFR heads are really that superior in design to these other quality heads?[/QUOTE]

I find the inclusion of a fully CNC ported head put up against as cast models an inconsistent comparison rendering the conclusion of AFR superiority worthless.

Let's get a set of the Brodix Track 1 200s fully ported and throw them in the mix

Why is it that all the comparisons that AFR does is with as cast heads not CNC'd ones? Not to mention they are all different CCs. They couldn't find a AFR 200CC as cast head? Now that would have been fair.

The only thing nice about the comparison is the "right" product came out on top.

Every single AFR comparison I have seen is always against an as cast head and always the wrong head in the lineup. In other words, rigged. This is just another example.

Perhaps that particular build liked smaller heads.

Thanks for making my point Ron. No head thread can go unanswered.

so what are trying to say ?...........leg humper capital..LOL

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DO you think putting a different sized fully cnc'd head against as cast heads that may be too big for the motor a fair comparison.

SO yeah, it is nothing but leghumping because as a scientific outcome, it is worthless..

What did I tell you yesterday mseven, any positive thread about any other head has to be met by equal time...someone was going to do it...it's a compelling sickness.

I'm done. Randy was right.

Did you read the whole page and all the responses? Even the guys on the chevy page said it's bs due to differences in dynos, etc. Those aren't "apples to apples" comparisons like the original poster wanted.

Not until you have the exact same motor, conditions, etc, will we never have a correct comparison. So why bring up this junk and stir the pot?

Matthew

Only guy who has a clue over there

http://www.chevytalk.org/fusionbb/showpost.php?post/1564321/

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When did they start doing a full CNC port on the AFR 180 "street" head as described in the link ?

When did Dart stop CNCing the Dart Pro 1 platinum head ? (Their website says its a CNC'd head)

When did Trick Flow stop CNCing the Trick Flow Super 23 street head ? (On their front page, they call it the Trick Flow "CNC" Super street head)

For what its worth, I don't make much of the aforementioned test either.... different motors on different dyno's.... but, if they had done the test on the same motor and dyno, there is no cylinder head in that group that has a significant advantage from a CNC or price point of view.

I come back to my comment that dyno's are junk.

I hate chassis dyno's. Unless you are using to baseline and consistantly use the same unit, you are asking for skewed numbers. Even then, it depends entirely on maintenance to the unit and weather conditions.

I do trust engine dyno's a little more, but they must be kept cool to work at their best. Again, calibration is key.

I harken back to my RC car racing days. I had a dyno for those little electric motors we used. With that, I would test the motor three times to let temperature equalize things. We would use the the last test and just accept it, due to the heat issues. Even then, these tests were simply a gauge... and the same motor tested on two of the same dyno's would give different numbers.

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I agree with what you say above about chassis dyno's..... particuarily if you have an automatic with a loose converter, they simply are not accurate, even the same one from pull to pull, the output is effected by the rpm you began the pull at and how quickly you went into the pedal. I've had multiple pulls on the same dyno on the same day, with the engine at the same temp for each pull and seen differences in torque of literally 80 ftlbs and peak HP of 30....

I doubt if I even have my new set-up chassis dynoed.... I'll use the timeslip instead, which is more fun than a chassis dyno anyway, and its cheaper too.

If you have a lock-up converter, you can lock it up and get better more accurate results, but, you do need to typically be a little higher in the rpm range before you lock it up considering even with multiple clutch disks, they do not like to be locked up at wot early in the power band.

The below is what Precision Industries says about chassis dynos.

http://www.converter.com/whatsnew_dynamometer.htm