Which Carb Gives a Balance of Power & MPG?

pick a carb on the small side, and then tune the sht out of it for gas milage/ slightly lean with a high/highest vac advance you can get away with, along with the hottest plug and comp ratio you can get away with, use a small runner intake and a multi spark ignition.

the rest of the motor is the other/performance side of it.

your done, you've basically taken a performance motor and neutered it's induction and rpm hp