There is a pulley you can use the retains the stock 7" diameter and skinny belt but has the smaller dish of the short shaft pulley. It has the exact same bolt and center hole pattern. It is a fomoco part. I got it from a junkyard, for a dollar. I posted the part number on it some time ago and you can do a search if you are interested. It keeps the pump from cavitating and the fan from overspeeding. The pump I used is a stock pump that I pressed the hub down on and cut off the extra shaft. It has worked great.
