I'm running (every day) a 3/8" v-belt pulley "early" waterpump w/adaptor plate on my 1960-235 in a 54-3100 truck. I used the Flex-a-lite fan #FLX-1615P (Summit Racing equipment @ $24.95)....had to scribe over the 5/8" hole and carefully file out to 1" to fit over the 216/235 pump snout. No spacer is needed on my setup and I have a fan/rad clearance of 1/2-5/8".
The 15" fan clears all my pulleys (Alt, Harmonic balancer and A/c compressor), there is no vibration and the truck runs below the center peg on the stock gauge w/180 thermostat. I have experienced no overheating problems even with the a/c functioning. Also, I am not running a fan shroud.
If you are concerned about extended periods of idling and are considering an 18" fan, I would do a mock-up to insure you will not have pulley interference. The FLX-1615P fan has a center-mounted blade which gives me adequate clearances front and rear. A rear mounted blade, like is used on the flex-a-lite #SUM-G4918 or FLX-1318 will not clear your pulleys and there is not enough room between the fan/radiator to use a fan spacer if one were available. Hope this helps!
Dave
