One can use factory parts with the late water pump. Here's what I did: found a 6-blade truck fan in a wrecking yard mounted to a 327 V8. Took the fan and water pump pulley home measured the difference in the offset between the V8 pulley and the 6-cylinder pulley. Bought a *new* water pump and pressed the flange further onto the pump shaft by the difference between the pulleys. Already had a four-row radiator out of a 2-ton AD so I modified its mounting flange to drop the radiator enough so the bigger fan would clear the lower radiator hose AND I mounted it on the front side of the radiator hoop using only three screws not six. It is possible to do this without putting the radiator in front of the hoop but you will skin your knuckles every time you take the fan bolts out, which you will have to do to change the belt(s). It's been like that for 25 years and never overheats, even in hot weather pulling a camper in the mountains.
Later I installed air conditioning using one of Patrick's bracket kits. I found that one belt would not drive all the accessories. Belts lasted about 5,000 miles tops. So I modified the bracket setup to accommodate a two-shiv crank pulley from an outfit in California and a two-shiv water pump pulley for Chev V8, specified for A/C. It's 10% smaller than non AC. So now I have two belts to drive the A/C and water pump/fan. Still need two belts to drive the alternator. That belt slips under heavy load. I'll have to modify that bracket. There are better brackets from which to start, like from the hot rod AC suppliers.
