[markeb01]

I think it's more likely both of the mechanical pumps have a common defect in them. I've analyzed the way the electric pump is made, and with the pump turned off you can actually see through the input and output openings. I actually purchased three mechanical pumps, the first one being the earlier style that can be disassembled to clock the housing. It turned out to be broken, and the connector link to the pump arm actually fell off.

I'm wondering if mechanical pumps just aren't made as good as they used to be since all new cars have been using electric pumps for a couple of decades.

I also found it interesting that my old/previous mechanical pump served for over 20 years with no hint of trouble. Trying to replace it turned out to be very difficult because all the new replacement pumps put out over 9 psi, and my Edelbrock carb can't handle more than 5. So for the first time ever I was forced to add a pressure regulator.