Remove the spark plugs so you are not fighting compression ( disconnect the crank sensor to disable fuel / spark )

Remove the oil pressure sensor, install a tube and a can if possible so you don't have a mess.

Crank the engine, see if you get oil pressure .

If not, leave the oil cap on, pull the air intake cross over tube ( the one that goes across the valve cover ) plug one of the breather ports in the valve cover, insert an air hose in the other and apply 2 or 3 PSI while cranking the engine. Don't add more pressure, you might push out a crankshaft seal if you do. There might be a breather hose in the intake manifold area that would need blocked also but I haven't looked at one recently.