The 1949 Ford passenger car came with the 4 blade fan & hub assy, which was a sealed ball bearing. Ford crimped it into place I think, as they never sold the bearing separately (or the fan or hub for that matter). This was the only version of this with the wide belt.
The 1942-48 cars, and the 1948-53 Ford trucks used that oil filled fan & hub assy, which had no ball bearing. Beginning in 1950, the cars changed to a 3 bladed fan/hub assy (like the 49 Ford car) but they had the narrow belt pulley.
It seems that I remember someone finding a way to replace the 49 style bearing. May have required some machining and installation of a retaining clip, in order to use a standard ball bearing which could be replaced easily. If anyone has done that, perhaps they would put their experience out on the forum.