What water pump issue? Use what GM engineered to work- - - -the whole system- - - -brackets, idlers, tensioner, belt, P/S pump (which can also be used to power a hydraulic brake booster instead of vacuum), A/C compressor, fan, and water pump. There is NO shorter system than a serpentine will give you, since it only runs one belt. Use an under-dash evaporator and fabricate lines to connect it to the GM radial compressor. It will cool well enough to turn that truck cab into a meat locker. Under-dash evaporator setups such as Vintage Air, etc. don't necessarily have to be used with their proprietary compressors. Think outside the box!
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!