How many CFM for my 340?

I've had an Edelbrock 750, Holley Street Avenger 670, and now have a 750 Holley double pumper on my 340 in my Duster. The 750 DP is by far the best driving and quicker carb out of those 3. I have no trouble driving it on the streets even having an auto trans. I do have 4.10 gears though.