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Thread: Vac secondary test?
          
   
   

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  1. #1
    Kevyd is offline CHR Member Visit my Photo Gallery
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    May 2005
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    Winnipeg
    Car Year, Make, Model: 64 Chevelle
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    Vac secondary test?

     



    What can I do to check if my secondaries are opening??? Carb is holley 750vac model 4160. Thanks.

  2. #2
    Kevyd is offline CHR Member Visit my Photo Gallery
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    Car Year, Make, Model: 64 Chevelle
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    vac sec

     



    That sounds good. I already have a lighter spring in there. I'm just not sure if they're opening at all! After a WOT run, the plugs are clean and white, showing a lean condition. I don't really feel a power surge, more of just a gradual increase of RPM. I've tried bigger jets-no dice. Plugs always come back the same. Is there anyway to ensure the secondaries are opening other than strapping it to a dyno and watching?????

    Thanks for the help guys/gals.

    -KevD

  3. #3
    BigTruckDriver is offline CHR Member/Contributor Visit my Photo Gallery
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    Car Year, Make, Model: hotrod
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    Go down the road about 10-20 mph then floor it!Be safe about it though!come up to speed and,let completly off of the gas as fast as you can.When you do this you will hear a big "woosh". This will be the secondaries closing.The best way to really adjust it,is to take it to the track and pay attention to your times,and MPH.I started with a weak spring and changed springs until ,my et,mph got it best.When my mph and et started to fall after peaking,I went back to the spring I put in just before.They sell a kit of a few springs(color coated) for I think less then ten dollars.Theres also a little red book holley sells.This thing is a Holley " bible" .Theres another that has more ibfo and tricks ,but I forget the writer.There is also plenty of pics. to help get a better idea of tuning your holley.
    Last edited by BigTruckDriver; 06-15-2006 at 06:52 PM.

  4. #4
    timothale's Avatar
    timothale is offline CHR Member Visit my Photo Gallery
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    Car Year, Make, Model: 16 t buckethotrod 17 horsless carriaget
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    I used to modify the linkage, bend 16 d nails weld them on the linckage so I had a mechinical kick in.
    timothale

  5. #5
    NTFDAY's Avatar
    NTFDAY is offline CHR Member Visit my Photo Gallery
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    Car Year, Make, Model: '66 Mustang, 76 Corvette
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    This book is a good source of information
    Last edited by NTFDAY; 02-04-2008 at 10:04 AM.
    Ken Thomas
    NoT FaDe AwaY and the music didn't die
    The simplest road is usually the last one sought
    Wild Willie & AA/FA's The greatest show in drag racing

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