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Thread: Difference between 1X4 and 2X4 Hp dominators

  1. #1
    Senior Member DYNO OPERATOR
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    Difference between 1X4 and 2X4 Hp dominators

    Ok, no one has had any questions in this section since April 3rd. What gives? No one needs to know anything about carbs anymore? Not even Quadrajunks?

    Well, I do. It's been asked before, I'm sure.

    What does it take to convert a Holley HP Dominator carb from a tunnel ram calibration to a single 4 calibration?

    For example a 1250 CFM - 80533 2X4, versus a 80532-1 single 4 application.

    The air bleeds are different.

    The linkage is different

    The metering blocks have a different number.

    But can you just change the air bleeds and use it successfully?

    80533 has progressive linkage, 80532-1 has soft progressive. Not a big deal if using a transbrake, right?

    80533 has .053" idle bleeds, .065" intermediate, and .036" high.
    80532-1 .051" .061" .028"

    Just change them out, right?

    Both come with 97 jets and blocked power valves, or 92 jets and power valves. Seen em both ways.

    80533 has 34R11972-4A metering blocks.
    80532-1 34R11972-5A

    This is what I don't know if it makes a difference??

    Maybe one has no power valve provision and one has power valves, I don't remember?

    But are there other calibration difference in the metering block, and does it make much difference if you decide to convert all the other items over from tunnel ram to single 4 barrel use??


    Also I have noticed that a lot of the new ULTRA HP Dominators are listed for 2 X 4 usage in the Holley literature and catalogs. Is that a mistake in printing? If so, there are no 1250 ULTA HP Dominators listed for single 4 use.

    Ok, if you made it thru all that, you are just as bored as I am waiting for it to quit raining on the weekends so I can go try out some carbs I spent all winter tinkering with.

  2. #2
    Senior Member RACING JUNKIE jmarksdragster's Avatar
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    The air bleed calibration on the stock 2 x 4 Dominators are usually better to start with for a single carb setup. Linkage differences is in the cam underneath to change the opening of the secondaries. Metering block difference is likely in the size of the idle feed restriction only. Unless it's a street car block both PV's, and make sure you have jet extensions and notched floats.

    Keep the .028 MAB's, start at .080 on the intermediate bleeds, and try .055 in the idle air bleeds. Jet it for best performance. If you find the car doesn't slow going to larger jets you will need to replace the metering blocks. As long as it does, once the jetting is optimized get a numbered drill set and go .010 up at a time on the intermediates. This will clean up the part throttle richness a 3 circuit carb is notorious for. If the MPH drops doing this go up one jet and it should come back. once you get to .100 and all is well try removing them entirely.

    http://racingfuelsystems.myfunforum.org
    Mark Whitener
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  3. #3
    Senior Member DYNO OPERATOR
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    difference

    Well put and appreciated.

  4. Racing Junk


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