Truck Repair: Oil Pressure, oil pressure gauge, oil pressure sending unit

Question
I have a melling high volume oil pump for a 302/5.0L. I nstalled this pump in a 1991 F150 truck 5.0L engine. I primed the oil pump with an old distributor and felt significant resistance on the drill I was using. However the factory oil pressure gauge does not budge......any ideas? I have oil in the oil filter and on the tip of the oil pressure sending unit. I even went as far as to squirt oil in the oil filter hole with an oil can in the attempt to get some oil into the pump in case the gauge was accurate and there was none.  Please help.

Answer
While you are running the drill; look inside the valve cover, when you can see a small about of oil moving in the valve cover you are safe to start the engine.  If you fire up the engine and after about 4-5 sec. you still have no oil pressure shut the engine down and research if you have a gage prob by installing a temp aftermarket gage.