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Thread: HP Dominator air bleed questions

  1. #1
    Senior Member DYNO OPERATOR
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    HP Dominator air bleed questions

    On the HP ( NEW STYLE) Holley Dominators, what are the differences between an 8896-1 and an 9375-1, other than the air bleeds? I know the 8896 is for single carb application and the 9375 is for 2 carbs. Both are annular discharge now, unlike the older style where only the 9375 was? Both are 3 curcuit now, where only the old stlye 9375 was?

    The high speed air bleed is .034" on the 9375-1 and the 8896-1 is .040". The idle and intermediate air bleed are the same on both HP carbs.

    So can you just change those air bleed and make a HP 9375-1 into a HP 8896-1, or are there other differences in the metering blocks or main body?

  2. #2
    Junior Member JOURNEYMAN
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    the metering blocks are the differance it is in the emollsionary circut how the air and fuel are mixed good luck joe g 8)

  3. #3
    Senior Member RACING JUNKIE jmarksdragster's Avatar
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    There is more that's different, if it's an Ultra carb with billet blocks you can change anything for make the calibration work for you. If they are cast blocks the idle feed is likely different and you have to drill them out, tap for set screws you can drill to suit. The calibration in the 9375 is a little better than the 8896, both carbs need metering help. What are you looking at using a Dominator on, and is there a deal on one you'd like to get?
    Mark Whitener
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  4. #4
    Senior Member DYNO OPERATOR
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    HP

    Thanks for the input guys.

    I run a PRO SYSTEMS 1050 8896 old style with billet annular boosters and relaceable air bleeds added. It works well with my setup. I am using an E-Z Plate restrictor system to slow down to 6.40 ET in 1/8 mile.

    I found a new style 9375 HP for a good price and cleaned and gasketed it. Just for a spare or to sell if the price is right. Would like to get it good enough so it will work on a 750 HP 496 BBC bracket door car @ 3000#. I put 90 jets in it.

    The air bleeds are stock. The idle bleed orifice is .034". My PRO SYSTEMS is .028". I was thinking of changing to .028" on this one too.

  5. #5
    Senior Member RACING JUNKIE jmarksdragster's Avatar
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    The old style body is a better one to use, but the HP is OK. If your idle bleeds are .028 or .034 you have an issue, it's likely the main air bleeds that small. The main or high speed air bleeds are closest to the vent tubes, the middle are the intermediate, the outer are idle. A 9375 comes with .034 mains, .063 intermediate, and .053 idle.

    Now for a suggestion on calibration, there are things you can do to make it much better if you can handle drilling and tapping small holes, the link below provides that info. To make it usable as is with a good cleaning, put .026 in the main air bleeds, take the intermediate air bleeds out and leave them out. You can try go up .002 on the idle air to .055. If it makes the transition too lean, light throttle surge or stumble,you can go back to .053. If the idle mixture screws end up between 1 1/4 to 1 1/2 out for best idle the idle/transition fuel metering is usually close. 93 square jets with no power valves will be a safe starting point with this calibration, jet for best MPH from there.

    http://motorsportsvillage.com/forum/...php?f=6&t=3742

    Mark Whitener
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  6. #6
    Senior Member RACING JUNKIE jmarksdragster's Avatar
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    One more thing, both the 9375 and the 8896 are 3 circuit whether old or new, the old style 8896 had straight bar boosters, the new annular, the 9375 both are annular. The 8082 is a 2 circuit 1050.
    Mark Whitener
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  7. #7
    Senior Member DYNO OPERATOR
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    HP

    Thanks for the info on the 2 curcuit metering blocks. I have looked into that before, just never followed thru. What specific benefits would you say it would be for a bracket race car?

    Also, yea I had my orifice sizes reversed. They are as you stated for a stock 9375 HP.

    So, the 2 curcuit moves the idle over to the former intermediate position?

    Also on the 3 curcuit, why do away with the intermediate air bleed on top?

  8. #8
    Senior Member RACING JUNKIE jmarksdragster's Avatar
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    Yes, a 2 circuit conversion moves the air bleed position to the middle, and the outer gets plugged to keep trash out. On a 3 circuit carb removing the air bleed leans the intermediate circuit some, the intermediate circuit adds way too much fuel at part throttle and is part of the issue. If you looked at the original old style 9375 carbs it came with no bleeds pressed in the body for the intermediate circuit. It was one of the best 3 circuit calibrations Holley had, even still most will run much cleaner, better, and more consistent with a properly calibrated 2 circuit Dominator. We've had them on engines from 500 HP to well over 1000 and never an issue with losing the intermediate fuel. The only thing you have to watch for is if you try to plug the intermediate jet on factory blocks you can run into an issue getting enough fuel through the main well, usually somewhere at or just over 900 HP or sooner if using oxygenated fuel. This is why we use a 2 circuit block or a BLP 3 circuit wide body block, they have no idle feed tubes in the mainwells to cause a restriction.
    Mark Whitener
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