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

This past winter I bought a slant 6 and trans that was sitting on the dirt on a barn floor.
I had to buy the whole engine and trans for the part that I wanted he wouldn't sell me just what I wanted from it.
This engine and trans was originally from a 64 pickup.
While I had it strapped to the trailer I cleaned the points checked the oil, (which was quite watery and soot black) but between the marks on the stick so I went with it.with a jumper wire to the +on the coil, a screwdriver between the lugs on the starter and a splash of gas in the carb it fired up and ran.
I was both happy and surprised it was just that easy. I have no idea how long since this thing last ran. It did leak out the crimp on the sending unit pretty bad. Steady dribble the whole time I ran it. Which wasn't long at all because I didn't have a radiator connected.

Fast forward a couple of weeks and I seen a wanted post for that particular oil pan, It was a weird one/ id never seen a front sump pan on a a Mopar before. That's more of a Ford thing in my experience.
Anyway, I got that pan drained, and off the engine. It had at least a solid 1/2" if not more of sludge that came up about halfway between the top of the sump and the gasket flange. One thing that was for sure/ the whole oil pickup was completely submerged in this thick sludge. It was like brown mayonnaise. But I looked up into the engine and the walls of the crankcase were absolutely clean. I never did pull the valve cover.

The guy who wanted that pan swapped me for the pan that was wrong for him and I bolted that pan and pickup back onto the engine, to keep it sealed and clean inside.