I had 650 double pumper on my stout 302 I had in a 63 falcon that was a screamer on and off the track.
I would recommend a smaller carb like the 650 dp or the 670 vacuum secoundary, they will give you great throttle response which will come in handy at the track footbraking or running in a dot class for them killer reaction times, but a bigger carb like the 750 or the 770 wont be quite as responsive but will give you more top end hp. Charles