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Thread: Power Valves and Jet Extensions

  1. #1
    BSKI Guest

    Default Power Valves and Jet Extensions

    I read on the Summit Racing website...... "Do not use Jet Extensions with Power Valves."

    I read all through the Holley Website and I have the Holley Tuning DVD and a Holley Tuning Guide and cant find anything about jet extensions and Power Valve combinations other than what is on the Summit Racing website????

    Any feedback would be appreciated.


    This is for marine application. So the use of jet extensions may have the same effect when comming off plane as hard breaking in street application?
    Last edited by BSKI; 04-24-2010 at 11:20 AM.

  2. #2
    BSKI Guest


    URL for Summit racing jet extentsion use and power valves:

    Actual Wording:

    Uncovering the secondary jets can cause a stumbling problme, and no amount of accelerator pump tuning will cure it. This occurs when a car leaves the line so hard that the fuel in the secondary bowl is pushed up against the rear wall, uncovering the jets. BG Fuel Systems and Holley offer jet extensions that correct this situation. Whenever jet extensions are installed in a carburetor equipped with a secondary power valve, the power valve must be removed and the hole plugged. Jet size must then be increased accordingly

  3. #3
    Join Date
    Nov 2009


    The thinking on this is that if your car is leaving hard enough to need jet extensions, then the avaialble fuel for the PV would not be there either. I would have to agree with the statement.

    1972 Rally Nova
    1972 C-10 Short Step
    1970 Rally Sport Camaro
    1986 Chevy Silverado K10
    2009 F150 Lariat

  4. #4


    power valves on the secondary side are 99% unnecessary. get rid of it and jet up accordingly.

    Last edited by zray; 06-11-2010 at 12:14 AM.

    '66 GT-350 Original Drivetrain, Sheet-Metal, Interior, & Paint

  5. #5
    464elcamino Guest


    Ok , I use a 1050 dom with 83 jets all around w a 5.5pv in front rear is blocked w jet ext, I have a small dead spot in the transition stage from idle to wot , should i up the rear jets to say an 87 to cure the dead spot ? It also has 31 squirters in it.
    Last edited by 464elcamino; 06-29-2010 at 11:15 AM.

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