The stock fan setup would be the best setup on a 54 truck with a 54 engine. If the engine has been upgraded to a later model 235 and you are finding a lack of clearance for the stock fan setup you need to check out the "water pump adaptor plate" conversion which properly positions the water pump higher on the radiator, gives you additional clearance for your pulleys/belts, provides you with the proper fan speed and let's you use a stock early waterpump that is available at most local parts houses.
The so-called "short water pump" addresses NONE of these issues and the overpriced pump is available only through mail order. The stock fan setup using the adaptor plate is simple, inexpensive, and once it's installed you'll not have to give it another thought.
I've outlined the adaptor plate install process in my Webshots Chevy albums.....hope this helps.
Dave