I have seen builders overlook installing one or more of the galley plugs on the front and or back of the engine.
Oil will pour out the back of the block and on the floor if it's the rear plug, or if it is the front ones it will not be visible (internal leakage) without removing the front cover (most often overlooked). You should be able to build 45-60 lbs with the drill and an un- modified HV pump. As Mike stated above, you must get
oil to the top end before you light the fire!. You must have a minimum of 3/8" of clearance between the pickup and the floor of the pan. Be sure the gaskets are in place between the pump/block & pump/pickup tube.
Rick
One last thought: The bypass plunger in the pump could be stuck open with some grit or foreign material, thereby puting the pump into bypass mode with most of the
oil being returned to the pan.