57 Ford car 9" rear end
 

I need to know the gear ration of a 1957 Ford Fairlane 500 9" rear end. Will it match up to a 1956 Ford-o-matic, 2 speed air cooled transmission and will it improve the gas mileage in a 292 engine with 4 barrel edelbrock carb with a 1962 Ford pickup distributor? Would appreciate replies as soon as possible. Thanks in advance.