It does sound like your rear seal may be compromised or possibly installed backwards if it's not a rope.
The 440 crank likely has slinger grooves around it. Small slashes in the seal area ////// one way or the other \\\\\\, depending on the intended crank rotation direction that are meant to direct oil back toward the engine and away from the seal.
What you don't want is a left rotation crank in a right rotating engine or a
right rotation crank in a left rotating engine,
either which would tend to pull oil into the seal.
I am not familiar with the 440 crankshaft and the small slashes being a part of the crankshaft.
On the GM engines, the seal surface is smooth and the "slashes" are within the seal.
As Dave says, they are there to wick oil towards the crankcase area.
Do you have a PCV operational on this engine? If not, you may be pressurizing the crankcase.
A leak down test before you pull it might provide some insight.
Yes..... a cylinder leak-down-test (not a cylinder pressure test... aka compression test) would be informative, but must be done prior to pulling the engine down.
Once torn down, this test can no longer be performed.
Is the oil pump new, or a used one that was "fine" on another engine? Either way you should check the pump to SM specs.
Are you seeing any air bubbles in the oil. A crack in the oil pickup tube threads can pull air into the oil.
Good point.
Again.... not familiar with the 440...... but over-filling the oil pan to the point of the crankshaft dipping into it may cause aerated oil, of which would lower the oil pressure reading.
Cut open the oil filter and inspect it for excessive metallic particles.
You might zip a valve cover off and make sure the rocker
shafts are on correctly. Oiling holes should be pointing downward and toward the valve.