Your 1406 is a squarebore 4 holes on the bottom of the carb ( like a q- jet) and a matches your cast intake. They are compatible.

The 2156 is a spread bore intake. One big hole. It is not recommended to put a squarebore carb on a spread bore intake. Any engine builder would not recommend it. You would have to use a spacer for it to work which then messes up the plane. I don't know all the details. I just know that it is not recommended by well know engine builders and racers. they advise against it. Always use the same type of carb and intake. If you want a spread bore intake you need a spread bore carb.