Well I hope there is an easy answer but here is what I have done.
Checked with a mechanical gauge, still 10 lbs at idle.

I removed the plug and spring for the pressure relief (Milodon Single line - new) to static pickup
I could not see the valve . I could not feel it with my little finger.

I changed the oil to Brad Penn 20W50 and a Napa Gold filter.

I started it and now have 0 (zero) oil pressure.

Note The line from the oil pump to the pan is very short (only a few inches)