Holley gave a fuel level spec for the 1920 carb. That put the fuel level right at the top air hole in the main well. Guess work, early version of 1945 did same thing .Later version may be not. There were different tubes used and different float settings early 3/64 and latter flush. Green dot is a good starting point for fuel level plus or minus 1/32. Keep notes for future reference. Todays gas with different specific gravity and density may affect fuel level using the old settings. Some have suggested lower float settings.