There were at least two different fan blades on 235 engines. One change might have taken place on second-series 1955 235/261s when the water pump was changed. The on-line Master Parts Book website is down - maybe someone will check a MPB for you.
If you send me the hole measurements, I have two different bolt pattern water pumps (the other difference is the diameter of the "snout" on the water pump - the size in the center hole on the blade).
