As a side note if the sender doesn't have a reversible float shaft you can "carefully" bend the float shaft 180 degrees close to the pivot point and accomplish the same effect.

1961 ford f500
1953 3100 five window (https://www.facebook.com/1953-Chevrolet-5-window-1533405913413610/)
1955-2 3200 big window (https://www.facebook.com/Leep3200/)
55yrs as a mechanic and retired. (kind of)