[Jack Shaft]

You upped the flow of the carburetor some with a different delivery system, the Marvel is an emulsion tube carburetor, a design that became popular the mid 30's. The Stromberg 97 uses the same design. The Marvel flows at about 80 CFM (cubic feet per minute) or so. The A engine in stock form flows at 160 CFM. CFM with a carburetor is the amount of air/fuel mixture it can flow at full throttle, CFM with an engine is the amount of air it will flow at peak rpm.. basically the A @2200 flows 160 CFM plus or minus. To achieve maximum efficiency from an engine matching CFM carb and CFM engine is needed.. With a model A/B ford four cylinder you're in luck, the Stromberg 97/Holley 94 used in over 30 years of flathead V8 engine production flows from 160 to 175 CFM depending on model.
As I built my engine I put my performance parts on one at a time, to feel the gain made by the component. Just putting the Stromberg alone on a stock engine really opened up the power in all throttle positions and increased economy some.. although it flows more mixture, it also raises efficiency due to lgiving the engine what it needs