Rebuilt Engine, Super Low Oil Pressure :(

I recently had my slant six machined and completely rebuilt. I did the rebuilding, a shop did the machining. It was my first rebuild and I made a lot of mistakes along the way, but I got her running and thought everything was going good until the oil light came on :(
I don't remember if the oil light came on initially when I started it, but it wasn't long after that it would flicker on and off.
Whats going on:
-No Oil to rockers
-Oil light flickers on and off
-Installed electric oil gauge, 7-10 Psi
-I pulled the filter and ran her for 5 seconds (maybe a bad idea) and she spilled about a half quart of oil, so the pump is working, but it wasn't blasting out (should it?). It was pulsing out maybe 1/4" high stream.
- Oil Pump is new

Any suggestions? How do I check to see if oil is getting to the journals? I really don't want to pull the engine back out but that might be what it comes down to. Thanks