1) Did you inspect and adjust "wet" fuel level after replacing the float? Ford intended actual fuel level to the the standard for proper fuel level calibration. Dry float settings were included in service settings only as a starting point. With all original needle valve and brass baffle washer parts Ford intended the engine to be fully warmed up and running at idle to inspect actual fuel level. Most modern replacement needle valves do not allow the use of the O.E. baffle washer. WITHOUT THE WASHER YOU DO NOT WANT TO START THE ENGINE AS FUEL CAN SPRAY OUT OF THE CARBURETOR QUITE A WAY. With modern valves the best you can do usually is full warm up the engine, shut it down, remove the carburetor cover, and do the fuel level inspection. If a change is required (bend the float tab up or down as required) you must reinstall the cover, run the engine a little, shut the engine down, and inspect again. Yes, it is tedious.
2) What is the fuel pressure entering the carburetor? Many 1960s Fords were built to handle 4 to 6 psig of fuel pressure to the carburetor. Remanufactured pumps and aftermarket pumps could get a 12 psig (or more) diaphragm assembly. If fuel is being pushed at anything above 6 psig there is a risk of over powering the inlet needle valve. A co-worker with a 1965 Mustang 200 I6 engine had his Ford pump fail. He bought a "will fit" pump at a parts store. The carburetor became more like a lawn sprinkler than a fuel control device. I asked him to check his fuel pressure. He found something like 14 psig (on his gauge). I suggested that he either get a correct factory pump rebuilt to factory specifications or install an adjustable pressure reduction valve or regulator and set the output to 5 psig. He installed a pressure reduction valve and set the delivery pressure to 5 psig and all was well again.
3) I did not see a mention of how the choke system is working. A friend drove his car to my home one weekend for me see what was wrong with his carburetor. The engine was barely running on a ultra rich air fuel ratio. The problem was the choke was fully closed and non-functional. A prior owner had installed an electric choke conversion and the wire had become disconnected somewhere behind the instrument panel. No power, no choke operation, worse, it stayed closed all the time. I ran a temporary ignition on power wire for him until he could find the disconnect and presto all was just fine again.
4) Have you checked to make sure no foreign material is fouling the inlet valve. It is not rare to find a tiny sliver of rubber from a rubber fuel line inside a valve. If the trash is too big to pass through it can sometimes fall back and be out of the way and sometime get caught between needle and seat. A tiny bit of debris in the valve can cause on again off again flooding problems.
