1988 Pontiac Grand Am Water Pump Pulley

I have a 1988 grand am that needs a water pump replaced. I have a mechanic but he does not have the puller or something that he needs to remove and install the pulley. We went to the local stores and they do not know which puller we need for such an old car. I was wondering if you knew what size or the number on the puller that we need to remove and install pulley to put in a new water pump.