It appears that I modified the vertical lever by the exhaust elbow. Not so. It already had that half-moon cut out. It barely clears the elbow. If it did interfere, I was going to bring the elbow out further before making the turn. But everything worked out fine - for once.

The elbow has a three-quarter inch male pipe thread where it scews into the block. The carburetor had to be temporarily moved out of the way to turn it in. It isn't tight as I didn't have the nerve to give it a final turn. But it is "gas tight" enough.

Notice the nice big fuel filter. The original was a teeny, coin shaped, and opaque. There is no issue with radiated heat on the filter or carburetor.