1985 Pontiac Fiero No oil to valve train

Engine Mechanical problem
1985 Pontiac Fiero 6 cyl Two Wheel Drive Automatic

Hi, so I have a 1985 fiero GT with a 2.8 liter V6. The car had a loud clatter from the valves and low oil pressure, About 25-30 psi on the dash guage.
I removed the covers and found a very loose rocker arm. I then removed the intake mainfold and found 6 rockers arms that had collapsed with broken retainer springs and some with the seats displaced. Thinking that this was the cause of the low oil pressure I replaced them all, set them and put the engine back together. And ran it.
First time out the oil pressure was still low aroung 25-30. And when I peak in the valve cover from the oil cap, I can't see any oil spurting on to the rocker arm at all.
Second time out the oil pressure never dropped below 40 and comes up to 60 on the road but the rocker arm I can see is still to dry.
What do I do, replace the oil pump or does this sound like a spun cam bearing, clogged passages. What would take out 6 lifters? I'm trying to, like everybody, save some cash. I can get to the oil pan easily, is there any way to tell from the bottom if its a spun cam bearing?