[Big hammer]

You could remove the lower half of the carburetor drain and dry it, fill the bowl to the proper level, letting it set over night to see if the fuel creeps and or leaking from the jets.
This week I've been looking for info on B zenith carb rebuild and I run across info that Ford recommended turning off the fuel. If turning off the fuel you still have a leaking problem, you need to repair the fuel valve. Also when you turn off the fuel valve and run it dry the carburetor will still have fuel in it along with fuel in sediment bowls which could weep into your carburetor.