Cleaning the oil pick up without dropping the pan?

I had an old 77 ramcharger, 318 that was sludged up bad.

I did this, fresh oil change, minus one qt, added a qt of atf.
Drove it for 500 miles, drained the oil was as thick as molassas, dripping from the drain plug, instead of flowing out.
Did the same thing again, next oil change after that the oil came out out real dark, but flowed good.

Put fresh full oil in it and changed it alot, then the oil started staying clean.

When I finally tore the engine down, in the truck because it was way lifted in the air.
It was actually some what clean inside considering when I first took the valve cover off, before the atf the sludge made a casting imprint of the valve cover when the valve cover was removed.

The oil pump pickup still sounded like a baby rattle though, because of pieces of plastic timing gears in it.

But the old girl did not loose enough oil pressure to hurt any bearings.

Old reliable, always got me home, and at the time I had to drive it over 100 miles a day to get to school and work.