You haven't latched on to a 351C iron pump vs the FlowKooler aluminum one then. About 2-4 lbs is more like it. And several (the Flow Kooler for sure) use improved impellers to move more water - aids cooling. These use a 3/4" shaft and sealed bearings.The saving of 17 ounces of weight is so infinitesimal as to bring zero advantage to you.
Use factory torque spec.I just purchased an aluminum water pump from Flowkooler and was wondering if I should go with less poundage or torque when tightening up them bolts; and how much less? Any suggestions or reference?