Jerry,
That is the big question. The pump is either not picking the oil up, or the system has a massive internal leak.
The system feeds the mains, rods, cam and lifters. Any of these could pour oil, but because this would require huge clearances, they would make loud noises too.
Maybe your oil pump retaining bolt came loose and the pump fell away from the distributor drive tang...I have no idea if this is possible, but it sure sounds cool.
My bet would be on a pump suction side problem, or a pump discharge piping problem. I'll bet the engine is mechanically sound, and with some minor work your stovebolt will be up and running again.
I think lots of noise would accompany any bearing or lifter failure.
Stuart
