Slant Six Oil light coming on — need a new pump?

Awesome, thanks for the input folks. I am going to try the method of least effort first—ie, a "cleaning" as described with oil and Marvel Mystery Oil, and few oil changes. If that fails, I will look into pulling the motor and replacing the pump.

So should I pull out that spring that appears to be inside the nipple? Or is that factory? I am wondering if it is part of the old seized oil filter that would not give up the ghost. I had to really destroy that old 23+ year old filter to get it off.

As for the discussion on fuel, I replaced the fuel pump, sending unit, and all fuel lines before trying to start the engine. The inside of the tank looked like it came off the Titanic! [EDIT: I replaced the TANK too!]

Oh, also, the idiot light sending unit doesnt want to come off. I can keep working at it, but is there any other location to hook up a mechanical gauge? Thanks!