Bill,

Is the carb original, or put on the car for racing?

The original (two barrel) is known as an Autolite/Holley, with an Autolite tag on the body, and "Holley" molded inside the float chamber. In actuality, it is a Weber design, copied with subtle mods from the Weber design.

Some Mustangs came with a single barrel carb, also an Autolite...not of Weber design.

See which you have, and we can talk.

Bill