Stumped and Frustrated with a Holley 670 Hesitation

Hey, had the same problem. Its your accelerator pump squirter, you don't have enough fuel to handle the hand off of from the jets to the power valve. when you go wot the transfer circuit takes time to hand off the duties form just jets to jets and power valve this is the duty of the accelerator pump and squirter. I had to go up to a 40 on my 750 to get rid of the hesitation and move my screw on the pump cam to the second hole. The spacer gives more plenum volume that has to be filled with fuel air mix this also will require more accelerator pump shot. The problem is a lean condition at wot due to insufficient pump shot.