I'd recommend installing a pressure guage and set the regulator for between 6-7 psi. During hard acceleration the fuel will go to the back of the primary bowl, away from the level control needle valve and if the pressure is to high you maybe getting to much fuel into the bowl for a second or two causing the fuel to flood into the venturis. You could also try this, adjust the float level so it is just coming out the tadle tale port on the side of the bowl then go down a 1/4 turn from there. Either way make sure your pressure is set correctly.