Casey,
Does your '40 shop manual tell how to do this?
If it were mine I would remove the fan blade and leave the pulley and belt in place then move the water pump forward to see if the impeller clears the block. If the impeller does clear, the pump can be removed with the pulley and belt still in place. On my '36 pickup that technique works.
Remember that it's an inanimate object and you're smarter than it is.
