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Thread: Newby Questions - 4150 XP 750 Carburetor

  1. #1

    Default Newby Questions - 4150 XP 750 Carburetor

    Just put in a new 383 stroker with 750 XP carb. It's in an Ultima track day type car. Was running a ZZ4, but for some reason decided on a larger engine setup! Might have gone a bit too far! Anyway, still running the engine in, but a couple of questions:

    1) Fuel bowl glass sight levels. The main glass is about one quarter up the gl**** and the secondary is about halfway up the glass. Are this the right levels?
    2) I get a lot of "hunting" on low revs, while driving at low speeds. How to best cure that?
    3) If I brake hard or go around a corner fast, engine seems to be starved. If I stop quickly, engine will die due to no fuel. Pump good & fuel tanks good for fuel delivery.

    I haven't had the carb setup at all, just out of the box so far. So guess a few tweaks are required. Any suggestions please. Paul.

  2. #2


    First off, I would raise the primary bowl to about 2/3 up the glass.
    2nd, I would get your IDLE MIXTURE screws set properly.
    Make sure your timing is good & stable. If using vacuum advance check to make sure it's advancing properly.
    Check your initial timing, if it's a got a decent cam in it, I would push my initial up to the 15-18° advanced.

  3. #3


    Many thanks. Sorry for the slow reply. Primary bowl is around halfway up now. Will put it up a bit.
    The timing suggested by the engine builder is 32° before at 3500 RPM. Solid roller Comp Cam.

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