There's no law that says the fan has to be mounted to the water pump shaft. With a little creative fabrication and a couple of pillow blocks and a piece of round stock you could center the fan on the radiator and run a short belt to a 2-sheave pulley on the water pump. Just thinking outside the box a little!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!