[carnut]

I think these pumps are being bought related to price rather than quality. This is a sheet metal pump so using the correct tools and torque values is very important to longevity. The weakness, I think, is the serpentine belt pulley attachment bolts on the pump which can work loose, they then loosen the impeller then the wobbling impeller damages the support bearing. So, buy DELCO new. Use the proper bolts on the pulley and carefully inspect the bolt holes on the pulley for fractures or elongated holes, use only shouldered attachment bolts and star washers and locktite them. If you hire it out check the price difference from an independant shop using a DELCO pump and the dealer using the same part. When I managed a Cad service dept in that era, 70% of the pump noises were related to fractured pulleys and/or impellers loose. The other 30% were bearing failures. On that old of a car I would also caution to closely inspect the belt tensioner and idler pulley. Ck the tensioner for being weak, the idler for being properly in line with all other pulleys.