Oil pressure issue

If you are getting oil out of the output of the pump with the filter disconnected, then the pump is obviously working, but it still might be a stuck "open" pressure bypass.

I would plug the end of the hose of the pump output and put a gauge on there. Even on the starter, or with a drill you should be able to generate 10 psi at least

Some time ago someone posted about interferance with the pump mount and ARP studs. The interferance broke (cracked) the pump. Some pans also interfere with the pump and I could see the same thing happening.

"If it seems" that the pump is outputting, I would connect the filter hoses together without the filter and see where you sit.