When I bought my truck the po.had installed a 59-235 and the pulleys didn't line up as well as they had about a six inch on the water pump which I felt could cause heat problems at slow speeds.
I used a pulley (around 4 in) and fan of a 50 car and supported the pump impeller and pressed fan hub down shaft until pulleys would line up and then cut shaft. This gives 3/4 in clearence between fan and rad, pulleys line better and use the smaller belt. I did have to redue the hub in order to use the older fan and did buy the lower hose offered by Carter
Lionel

1950 3100 5-window