If the truck is original or stock I would look at an alternative to moving the radiator. Any time I've seen that done it looks butchered.
As to clearance between the rad and the fan I must have the tightest. Its about 1/4" and if I blow a fan belt the rad would have to come out to change it. It is too tight and I'm not happy about it but its been that way for about 12 years. I just make certain my motor mounts are good.


1949 Chevy 1/2-Ton
"Sedgewick"
In the Gallery
1989 Caprice