I can't see how float level will have anything to do with whether it runs rich or not . If you raise the float level high enough it will cause the engine to starve for fuel under load. With the float too high it would run lean and backfire but it would not run lean and smooth . If the float level is too low it would cause leaks and stalling apon braking or coming to a stop but wouldn't cause the engine to run rich as you describe. If the running rich problem began after installing a carburetor kit, that will more than likely be the problem. I would try replacing the jets that you removed. The jets in the kit may be too large. The knob on the choke rod controls how rich or lean the engine runs. Make sure that the knob on the choke rod is tight and not just spinning on the choke rod shaft. Turn the knob clockwise to lean or counter clockwise to richen the mix . Zenith carbs usually run best with the GAV knob turned 1/4 turn off the seat when warm. The adjustment screw with the spring on the front of the carburetor housing controls the air mix for the idle circuit . Tightening the screw richens the idle circuit, loosening the screw leans. The idle air adjust screw usually idles best with the screw one and one half turns off the seat.
I wonder what spark plug that you are using. I had similiar problems when running Motorcraft TT 10 or Champion W 16 Y spark plugs on short stop and go drives. Champion W 18 spark plugs are hotter and run cleaner for most model A short around twon drives. I would take a look at the air gaps between the rotor tip and the contacts in the distributor cap. An air gap of .035 will give you a hotter spark at the spark plugs and help better ignite the fuel and burn off the soot. If the coil is weak and the heat range of the spark plugs is too cold, the spark plugs will continue to run black and sooty . Most times running rich gets blamed on the carburetor . I have found the problem to be weak ignition in most cases. ust my thoughts.
