Why oh why. Sudden oil pressure drop.

I would not put air in there. Chances that the sender port is plugged is zero. Well, LOL pretty small.

1...Hook up manual gauge. You can even use your compression gauge, mine uses common air hose quick connectors that make it easy to adapt
2...If pressure is low I would start by pulling and critically examining the dist, intermediate gear, and look down there with a flashlight and see what. Damaged cam gear, filings, etc.
3...Then pull oil pump and examine, look for busted 'o' rings, etc.
4....It is not that "un" popular to have a cracked pickup tube.