nystreetscened,
I didn't know you had the engine sitting up that long. What might be wrong then is you spun a cam bearing on initial start-up. Might want to empty the oil out of the pan and check for metal. My engine had set up for some time before I started it and the same thing happened. I spun the 3 center cam bearings, my oil pressure did just like yours it was around 40 cold and would go to about nothing once it warmed up. Drained the oil and saw bearing material. Pulled the engine and pan and the center cam bearing was sitting in the pan. Had the block cam journels cut for oversize cam bearings and had to get a new cam as the journels on it were tore up. I had even primed the oil pump really well before starting it up but it didn't help.
I hope you don't have the same problem.