most likely will be NS1 or only available as a reman, which most likely will be no different from what you could get at napa, carquest, etc.

AFAIK, there's no special "heavy duty" waterpump, just the 6 blade and 8 blade, and the determination on which to use is determined by application (A/C or non A/C, the water pump pulley is different sized between a/c and non a/c)