I know a single 800 will work. That is what we run on our 67 coronet wagon in NSS. Corky Bumpus on a mopar and Jim Netherland on a buick also run a single 800.

We worked with an avs and the hesitation is hard to get rid of. Not a bog but a slight hesitation. I would go with an old style 800 performer series carb.It will work with some tuning.

Something else worth looking into. There is a new edelbrock carb. It has annular boosters to help it during the transition. I have not looked at the sizes available but its worth looking into.