Pumps with the WX128 casting number were a very common aftermarket replacement pump or maybe even a field replacement not recognized in the factory parts manuals. (So many XK-120s have them that it's hard to imagine they were not installed by dealers.) These pumps incorporate the same bearing and seal as all later pumps so they are functionally superior to the "original" XK-120 pumps. Most of the rebuilt pumps we have will not be supplied with a pulley because they are very, very easy to break.
This is a rebuilt part with a core charge. For more on core charges and our rebuilt parts policies, click the Documents tab and double click on “Core Information Sheet 8 10 2015.”