Stumped and Frustrated with a Holley 670 Hesitation

What do the plugs look like? They're the best indicator of whether it's lean or rich. My initial thought is the floats are too high or too low, but I wouldn't mess with anything until I knew for sure. You need to verify whether it's a fuel or ignition problem. High secondary resistance in the ignition system will cause hesitation problems. (problems can occur if on the primary side also) Check your car & rotor real good for any signs of burn through. I've seen many rotors burn through & cause the voltage to short right to the distributor shaft. initially the problem will only happen under load.