My model A had a 327 in it. I put a new carb on it, an edelbrock thunder series 650 CFM. It would do the same thing, bog when you slammed the pedal down. I cured mine . The accelerator pump has a linkage on it with 3 holes. I moved the linkage so it was in the hole that gave it the biggest stroke. It cured about 90 % of the bogging problem and was free. Also have you doublechecked the carb gasket ? When bought my carb the parts guy gave me the wrong gasket , and it would not let the secondaries open. Check to make sure your secondaries open fully when in wide open throttle.