Carb problems

ive got a holley 650 CFM 4150 double pumper
heres the deal... when i first got the car this carb was on it.. it would only idle and you couldnt get it off idle or it would die... in any gear..so we rebuilt the carb.........runs good , idles nicely .it will sit and purr for hours and it revs decently..in park and neutral....when you put it in a forward or reverse gear it will idle fine but it doesnt want to get off idle or it will try and die... you have to quickly rev it to around 2500 or more...but then your doing burnouts everywhere just to move...i know it doesnt have the same problem as earlier...i think part of it needs adjusted...but i dont know any ideas??
also i know this carb is too big..thats for another day
im trying to teach my sis how to drive and she cant with this beast now
thanks
john

Sounds like it could be an accelerator pump or float bowl problem right off the bat.

ive already set the fuel level in the float bowl....so i would be really surprised if it was the float..........i suspected the accelerator pump...seeing it has a hard time making the transition from idle