Carb cfm with ported heads?

Are you looking to improve 1/4 mile times?
If so, other things in the combo would help more
If a street car, i would probably keep what you have
In a “ racy” smallblock, i have never ever seen a bigger carb not ET better than a smaller carb. Never

I had a “ hot” 318 motor in another car couple of years ago. Ran 11.60’s. It was a tenth quicker with a good 950 than with a good 750. And thats just a 318.