Carb tuning, accelerator pumps.

No play in pump arm, 30cc pumps, 31 squirters. If car hesitates when snapping throttle open, increase squirter size OR pump cam ramp. If car puffs and feels a little soggy down low, go to a smaller squirter like a 28 OR a milder pump cam ramp. It is trial and error. Heavy cars and/or not enough converter/gearing are MUCH pickier about the accelerator pump.

Something to thing about! If you leave at say, 2000 rpm your car is NOT leaving off of idle and you have already used up some of the pump arm travel because the throttle is partially open! You CAN adjust it from there so you get the full pump shot. Yes, it will hesitate around the pits off of idle but WHO CARES if it is a race car.