Michael,
It might help to know which truck your are talking about. I had the same problem with my 1950 Chevy COE that came with a later 1958 235. They had torched the top radiator panel when moving the radiator forward to make the engine fit. In the restoration, I found a new radiator panel and installed a short shaft water pump. I ended up going to NAPA and getting a flat six bladed fan, coupled with a fan spacer. You need the spacer to keep the fan from hitting the harmonic balancer, but when it is in place the stock fan hits the radiator. Thus, the aftermarket fan that is "thinner" from front to back when installed.

Another option is using the relocation plate for the 216 water pump on the 235, to keep the fan centered on the radiator. I don't think you have fan clearance problems with that solution although I am not sure so someone can correct me if that is not true.

Good luck,
Kent

1937 Chevy 1/2 ton
1942 Chevy 1/2 ton
1947 Diamond T Model 509
1951 Chevy 1/2 ton
1950 Chevy COE Model 5700 ~ "Barney" ~ And more pix