How can i improve my oil pressure in my 360 magnum

SpeedThrills said
You say the bearings "looked good". Did you at least use Plastigage? Bearings are available in undersize, by the thousandth, if need be.

I had the machine Shop check all the clearances and I used plastigauge when I originally built the engine.
I remember shimming my oil pump on another 6 cylinder engine years ago. Perhaps I need to do the same on this engine