The 216/early 235 water pump has a pulley that's pressed onto the shaft, and is not replaceable without some serious pulling and pressing. There are two different belt widths, depending on the year of the engine it's intended for and the width of the crankshaft and generator/alternator pulley grooves. The later model pump that fits the 55-up 235 has a small round hub and a bolted-on pulley.
It is possible to machine away the pulley grooves on the early pump and adapt a pulley for a MOPAR V8 for applications that use a 2-groove crankshaft pulley. This makes it much simpler to mount accessories like A/C compressors and power steering pumps.
http://www.hunt101.com/data/500/medium/DSCF9963.JPGhttp://www.hunt101.com/data/500/medium/DSCF9960.JPG]
http://www.hunt101.com/data/500/medium/DSCF9968.JPGhttp://www.hunt101.com/data/500/medium/DSCF9972.JPGYes, I do oddball stuff to stovebolt engines!
Jerry