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Holly Carb adjustment with vacuume gauge?

Discussion in 'The Hokey Ass Message Board' started by solo_909, Aug 26, 2012.

  1. solo_909
    Joined: Apr 9, 2006
    Posts: 1,765

    solo_909
    Member

    Do any of you guys know how to adjust a holly carb with a vaccume gauge? Is it the same way as an carb where I just adjust the adjusting screws till the valve peeks on the gauge for each adjustment screw?

    Thanks!
     
  2. Deuces
    Joined: Nov 3, 2009
    Posts: 18,712

    Deuces
    Member
    from Michigan

    What size Holley do you have???... Not that it matters.. Just curious..
     
  3. squirrel
    Joined: Sep 23, 2004
    Posts: 46,864

    squirrel
    Member

    I think I tried it 30 some years ago, then decided to use the best lean idle method...screw both screws in till they seat (gently) then out a turn and a half. Then when it's idling (after it's been warmed up) turn them both in a bit, see if idle speed goes up or down, repeat this procedure trying both in and out till i get the best idle combined with the fewest turns out...then if it's a hot rod with a big cam, back them out a little bit more, if it's a stocker leave them there.

    then test drive, if it hesitates off idle I'll richen it up a little, etc. till it runs good.

    It would be helpful if I'd put a vacuum gage on and see what this looks like on the gage, but I never have.
     
  4. modeleh
    Joined: Oct 29, 2009
    Posts: 380

    modeleh
    Member

    I adjust timing and carb with a vacuum gauge, going for the highest most stable reading you can get. I have also done hydraulic lifter adjustment this way but it is messy. The vacuum gauge is one of my favorite tuning tools, and if you mount one on the dash like some 50s & 60s cars had from the factory, it will also train you to drive towards better efficiency.
     

  5. there you go
     
  6. squirrel
    Joined: Sep 23, 2004
    Posts: 46,864

    squirrel
    Member

    I have a vacuum/boost gage on my 55, and I love to get the boost up as high as I can. I don't think I'm properly trained to use it for economy
     
  7. solo_909
    Joined: Apr 9, 2006
    Posts: 1,765

    solo_909
    Member

    Well I had a local classic car shop adjust it and he adjusted infront of me like you said and by ear. I was just curious because I could never get my edebrock to a good place. I called edelbrock and they recommended me using a vacuume gauge, so I did and it ran perfect. I was just curious
    If it was the same way.

    Cool, I'll check it with the vacuume and see what happens. Thanks!
     
  8. Jimbo17
    Joined: Aug 19, 2008
    Posts: 3,736

    Jimbo17
    Member

    I find that the vacuum gauge is the best way of setting the carb and the timing period. Make sure you are connected right off the manifold and have a good connection.

    You want the most vacuum you can have on the carb and with the timing I do the exact same thing and then just back it off a little and you should be good to go.

    If you leave the timing where you have the most vacuum it always seems a little to advanced for me at least with a 350

    Hope that helps. Jimbo
     
  9. solo_909
    Joined: Apr 9, 2006
    Posts: 1,765

    solo_909
    Member


    I appreciate it! Thanks!
     
  10. I do the 1.5 turns out, get the highest reading on the vacuum gauge and if I'm really fussy, I'll listen to the exhaust while a trusted helper find tunes the carb... just a 1/16 th turn in... perfect!

    Bob
     
  11. I do it both ways, but just remember that you have to wait a little bit between adjustments for the carb to react.
     
  12. Deuces
    Joined: Nov 3, 2009
    Posts: 18,712

    Deuces
    Member
    from Michigan

    Last 302 I built, I got 23 inches of vacuum @ 750 rpm... It idled oh so sweet!..:D
    I also rebuilt the Holley 600 #1850..;)
     
  13. solo_909
    Joined: Apr 9, 2006
    Posts: 1,765

    solo_909
    Member

    How long? My edelbrock would adjust right away.
     
  14. Mr. Jean
    Joined: Dec 13, 2007
    Posts: 604

    Mr. Jean
    Member

  15. Deuces
    Joined: Nov 3, 2009
    Posts: 18,712

    Deuces
    Member
    from Michigan

  16. Oldsmobucket
    Joined: Dec 11, 2005
    Posts: 330

    Oldsmobucket
    Member

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