Selecting Cylinder Heads

Discussion in 'Engine Topic' started by Riley, Mar 13, 2021.

  1. G72Zed

    G72Zed Veteran Member

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    The intake is the factory GM dual plane that comes with the "602" crate. Stock, as delivered, no mods to the plenum divider as it's against the rules, and now it's "sealed" so not removal is allowed. I have used a 1/2 dozen spacer styles to "tune" the intake/HP/TQ curves/settings.

    The carb starts off with a 650HP part # 80541-2 right from Holley. Then I do all my work for my "602 Crate" program, and there lies the magic as you see by the AFR's. It idles at 13.4-13.6 AFR's so it's good & clean, the trick is in the transfer/bleed/PV circuits to set the RPM activation of the mains, this is an awesome race carb, but not quite the best choice for a "street" type deal, that's a different setup that I custom build.

    FWIW same exact carb is spec'd for the 358 DIRT Modified, but not the same setup at all as they are in the 580-600HP range with 10X Octane with whatever % oxygenated fuel. Open plenum intake, so spacers vary in style.

    Does this help you out Ed, if not, sorry for being vague, but I work for many "Race Teams" and the NDA must be held in high regard.
     
  2. Titan77

    Titan77 New Member

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  3. sandlapper

    sandlapper Veteran Member

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    and, apparently, effective salesman as well. :rolleyes:
     
  4. sooner

    sooner Veteran Member Lifetime Gold Member

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    Ok ill bite. So what is wrong with those heads at that price point?
    Before you say flow numbers, id encourage you to go and look at the flow numbers for both the NKB (they are proheader and come in proheader boxes) and Dart heads tested on other benches. Skip's bench looks to be a little tight on both.
    Can you find another person selling heads at that price point that list the components that are in their heads? If so are they equivalent to the components in the link posted?
     
  5. Andrew Talbert

    Andrew Talbert New Member

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    I agree! If I had an unlimited budget, it would be AFR's hands down. You can't go wrong there, and they would sure be pretty sitting on top if nothing else!
     
    Last edited: Mar 19, 2021
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  6. G72Zed

    G72Zed Veteran Member

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    I work with Unlimited budgets in some cases, the AFR's are not part of the program....not saying they don't flow the numbers (mostly) or make power, they do, but there have been some issues (just like the plastic-composite intakes).

    The holly grail of the CFM race war on the bench is down on the list of making power. Just saying.
     
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  7. DesmoEd

    DesmoEd Veteran Member

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    Thanks, I was curious as that Vortec motor made very good numbers. Didn't expect any trade secrets:) just basic info on type of carb, intake, and jetting if possible. Those tq numbers are strong, how far below 3500 does it exceed 400ftlbs?

    I'm running the street HP650DP on my 355 - I cleaned up the idle by changing the bleeds and tuned the acc pump/cam but thats about as far as I have gotten on mine without use of a wideband or chasis dyno.

    Interesting in that your classic HP comes from Holley with 70 pri jets and a rear PV vs 69 pri jets and no rear PV on the street HP
     
  8. muscl car

    muscl car Veteran Member Lifetime Gold Member

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    I think AFR is still trying to regroup after their lead engineer/ designer , Tony Mamo left to start his own business "Mamo Motorsports "

    I think when Tony was there AFR had the best design cyl heads
     
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  9. 1980RS

    1980RS Veteran Member

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    I was able to run high 10's with a pair of mild ported "stock size" valve 170cc Vortec heads. There is a guy out at the same track that runs a 2nd gen Camaro with 195 AFR heads, he runs the same ET's as I do with about 3 more MPH. While AFR's are great heads there are a lot of other heads that are great also. If I had the time I would put my AFR 210's on the same engine but they are reserved for another engine.
     
  10. muscl car

    muscl car Veteran Member Lifetime Gold Member

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    I like my AFR cyl heads !!

    20200413_172220.jpg
     
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