I have (2) modified 502's and (1) is misbehaving. When I swap carbs the problem is transferred to the other motor so it is carburator related.
The suspect carb idles fine. Once I drop in gear and attempt to throttle up, it starts to boog and poof through the carb and then stall. If I work the throttle back and forth I can manage to get through it and get up on plane and once the motor gets past 3000 rpm it is fine. the plugs look light tan colored and I suspect maybe lean condition exists. Any help for be greatly appreciated.
What do I check for?

Here's more info:
Holley Dominator 1050's
Single Plane Merlins
Comp Cams 650/660 lift, 278/288 dur
CMI headers
Ported iron heads with 9:5:1 comp

accelerator pump

I would guess accelerator pumps also. ? Is that duration at .050"?

Chris

Rebuild it. probably the accellerator pump. May have a cracked diaphram. Check for an external leak to avoid a "boom".

I love this board. Good people always willing to help!
Appreciate the responses everyone.

Could be a couple of things, but I'd focus on the accelerator pump. It's sole purpose is to cover a temporary lean 'hole' when you open the throttle. Could be the adjustment of the actuating arm, the capacity of the pump (cc's) or the profile of the actuating cam.

Another part of the accelerator pump circuit that I have had problems with is just under the jets that spray the fuel into the carb from the accelerator pump is a ball. Sometimes this ball sticks & will keep fuel from being injected into the carb.

Look down in the carb & move the throttle, If you do not see fuel spraying you have found your problem.

quote"Look down in the carb & move the throttle, If you do not see fuel spraying you have found your problem."
Then replace the accelerator pump!