[Steeveedee]

How much difference is there between the diameter of the fan and the diameter of the shroud? There is usually about a 1" difference that is divided up across the shroud, so 1/2" of clearance all around. If you don't have AC, that 4 blade fan would be OK, but as has been mentioned, if you use a clutch fan, you'll get a mileage bump (and a bump in performance, too, since the fan will freewheel to some extent when you accelerate). The clutch fan might also bring the fan into the shroud enough for better coupling. Nice looking truck, BTW. I wouldn't mind a bit finding one like that for myself!