AC Model C Carb

I have a 1947 Allis Chalmers model C and I rebuilt the Zenith carb from a kit. It went back together just fine but gas keeps draining out the air intake ports on the right.  The Needle Float Valve is the same size and shape as the original.  Am I to assume the floats are not raising high enough to push the needle valve up into the brass barrel that houses the valve in order to shut off the flow? The new floats are almost identical in size, shape and positioning as the original.  

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I preach this all the time, but one of the biggest problems with dirt and debris is the inlet port to the needle and seat needs to be spotless. Dirt, rust, and debris build up in the unused threads where the 90 degree elbow screws in. Also, the inlet port walls, and the back of the inlet port trap rust, dirt, and debris and the new Viton needle valves catch that minute dirt and it hangs the valve open. The end result is flooding and or overfueling. The best thing to do is remove the Carb, lift the top off and run a bore brush in a drill in and out of that bore till it shines! Once all the rust n' muck is outta there, you should be good to go. While you have the top off, take the pivot pin out, shake the floats gently to make sure they are not taking on fuel. If they are, you will hear a sloshing noise inside the floats. This would cause the same problem and a set of floats are in order. HTH
Steve@B&B