OIl pressure, cranking engine
You need to turn the engine over by hand. There is a hole in one of the cam journals that alternately routes the oil to one side then the other on the top end. If the hole is not lined up no oil to the top end.
Get a helper to run the drill then slowly turn the crank, when the holes are aligned you will see oil up top. Keep turning until you get oil on the other side.
If you don't get oil on the drivers side the inner galley plug may not be installed. Look in the distributor hole (I am assuming small block) on the block torwards the drivers side and you should see a pipe plug. If its missing I hope the engine is not installed because you will need to remove the outer plug on the back of the block under the flywheel/flex plate to access the inner galley plug.