I don't see if you said you had oil pressure at the gauge when it was running, did it? If so that would indicate the oil gallery has pressure.
Your intention to drive the oil pump w/a drill to see if oil flows to the topend is good. Don't run the engine anymore until you can verify oil pressure at the gauge (or at the T fitting that feeds to the gauge and oil distrbutor).
The oil line thats behind the side plate if not positioned just right can rub against a push rod and get a hole worked in it. So if your drill test indicates oil pressure at the gauge but not to the topend, pulling the side plate would be my next check.
Good luck
Dave
