[Mr.Fixit]

I bet it's because the float bowl vents dont have the good "whistle" style baffles in them. Under braking, the gas runs up and out of the bowl vent, flooding the motor. If the motor is rich upon refire this is it. Take the bowls off, get two of the white plastic Holley bowl vent baffles, and you're most of the way there. Set the float height to the bottom of the sight plug, so the gas dribbles out if you rock the car by the fender. I doubt that it's a going lean condition, or youd probubly hear a "pop"as the motor stalls.