I have a 1956 235 inch in my 49 half ton. I did not install it. The fan is about a quarter inch at best from the radiator. Changing the fan belt would require removing the rad. I have driven it this way for about 20 years. I am still wary.
I thought of removing the fan and installing an electric fan outboard of the rad to solve the problem. I have no overheating issues with the truck and I know about the short shaft pumps but I believe installing one (drilling and tapping holes) is beyond my skill set.
Another option would be to get a 235 pump as I have now and shorten the shaft. The fan pulley in that case may rub against the block and of course I wood need to align the generator pulley with the shorter shaft.
I think an electric fan might be the easiest solution.
