Doug,
I think you may have been looking at a stock 54, 55 truck water pump, they have the fan mounted on a pedestal with two different width belts.
Bill

55 Vicky & customline
58 Rack Dump, 55 F350 yard truck, 57 F100
59 & 61 P 400's, 58 F100 custom cab, 69 F100, 79 F150, 82 F600 ramp truck, 90 mustang conv 7 up, 94 Mustang, Should I continue?