understanding a low oil pressure 360

I don't post here much, but none of my research has produced much. Everyone always pointing to galley plugs or just random things to attempt to help.

360 rebuild
5w-20 lucas break in oil
solid lifter roller tipped adjustable rockers
new bearings fresh hot tank reassembled, 90-degree oil filter housing with WIX filter.

Running idle cold oil pressure at 10 psi
spun the oil pump with a drill pre-start up and post start up; I get 25 psi with no oil up top and when I position the cam and crank 2 separate positions both rocker shafts get 25psi. low speed on my drill, I increase speed pressure goes up.

it seems I have all plugs in and have verified all but two, not sure if 7.5 inches down the oil port on the China wall indicates no plug or if it's there, but through all I have read it's there. and behind the oil filter housing haven't looked yet, But I remember seeing one, but I'm old and have slept and drank since then.
spun pump with oil filter off (nice mess because it wasn't on purpose) and getting a lot of oil there.
Rockers are getting a lot of oil while I spin the pump manually, flows out of heads on to the headers So I'm getting oil throughout engine.

running out of possibilities.

Kind of thinking out loud here: If no plug under the 90-degree oil filter housing, should be no pressure at all.
if the pump where bad there would not be pressure or very little while spinning manually.
Best I can tell the oil, while engine running, is leaking off somehow and somewhere or not getting picked up.
I was mulling this over and I can't think of where the oil is going. only thing I can come up with is that the pump (suction side of the milling pump) is pulling air at a higher rpm than the drill is making, or the higher rpm is producing enough pressure to overcome the pressure side but before the pressure gauge, gasket. I did use the oil pump gasket and torqued to spec.

I have compared pump drive shafts and I get full engagement.
When I did start the engine, it sounded good nothing rattling or knocking or pinging.

Does anyone have a different theory? same? looking for ideas before I remove the oil pan and 90-degree oil filter housing oil pump engine and brainstem.
thanks y'all
Don't know if someone else has brought this up, but years ago I had the same problem on a 360. What it ended up being was the plug under the oil filter mounting plate that I wasn't aware of it was taken out at the machine shop and I didn't know about it.