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A little tuning help?

Wahoo1

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So, when i floor it from a stop I'm getting a hesitation with a little pop from the carb then it takes off and pulls hard. I know for sure some of you guys will know what carb issue this probably is. Any help would be much appreciated. I guess I should add that's it's a 383" with aluminum heads and intake with a proform 750 carb.
 
Sounds like you're too lean on fuel, but check timing first.
 
I found this on the HotRod Network years ago and saved it. Check this out on your car.

The amount of fuel delivered by one accelerator-pump stroke is determined by the pump’s capacity and the profile of the pump cam. The time it takes for that fuel to be delivered is controlled by the pump-nozzle size. A larger pump nozzle delivers the fuel much sooner than a smaller pump nozzle. During acceleration tests, if you notice that the car first hesitates and then picks up, it’s a sure bet the pump-nozzle size should be increased. A backfire (lean condition) on acceleration also calls for a larger pump-nozzle size. Conversely, if off-idle acceleration does not feel crisp or clean, the pump-nozzle size may need to be decreased. Holley accelerator-pump nozzles are stamped with a number that indicates the drilled pump hole size. For example, apump nozzle stamped “35” has a 0.035-inch orifice. Pump nozzle sizes areavailable from 0.025 to 0.052 inch. Whenever a 0.040-inch or larger accelerator-pump nozzle is installed, the “hollow” pump-nozzle screw (PN26-12) should also be used. This screw allows extra fuel to flow to thepump nozzle, assuring that the pump nozzle itself will be the limiting restriction in the accelerator-pump fuel-supply system.

When changing the pump nozzle, it’s best to jump three sizes. For example, if there’s an offline hesitation with a No. 28 pump nozzle, try a No. 31 pump nozzle. If you must use a No. 37 (0.037-inch) or larger pump nozzle, then also use a 50cc pump. A 50cc accelerator-pump conversion kit is available under Holley PN 20-11 when maximum pump capacity is desired.

Once nozzle size has been selected, the accelerator-pump system can befurther tailored with the pump cam. Holley offers an assortment ofdifferent pump cams, each with uniquely different lift and durationprofiles that are available under Holley PN 20-12. The cam profileaffects the movement of the accelerator-pump lever and, subsequently,the amount of fuel delivered by the pump nozzle.
 
Great post 'moes' that tells it all, but I'd check timing first to take that out the equation.
 
Yep check timing, and before you switch any parts on your carburetor, make sure the accelerator pump arm on the primary side is adjusted properly.... needs to move and give you a shot of fuel at the same instant there's any movement in the throttle linkage. You also need to be able to slide a .015 feeler gauge between the arm and the adjuster bolt head when at full Throttle, to prevent the arm from bottoming out the diaphragm and damaging it.(that's my screwdriver pointing at it)
20170710_143200.jpg
 
Yup beanhead, from what I've heard on this forum you now have to check stuff even on new parts to make sure it's right. You gotta have a baseline to start from.
 
Yup beanhead, from what I've heard on this forum you now have to check stuff even on new parts to make sure it's right. You gotta have a baseline to start from.
Had to do this on my demon (purchased back in '08 when they were still a company!) I had a slight hesitation at first stab of the throttle as well
 
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