Oil pump priming question

I have a 71 Duster I just dropped the 340 LA engine back into. Went to prime the oil pump/engine with the hex head tool and drill. After 4 to 5 minutes of priming the oil gauge only read about 5 -10 psi. I took the oil gauge off and blew compressed air into it and the gauge moved to about 20-25 psi. Then I primed the engine with the oil gauge of to see if oil was coming out and just a drop every now and then. When I took the copper gauge line out at the block and primed it, tons of oil cam gushing out. So I know lots of oil is getting to the start of the oil gauge line just not going through it. So I bought a new copper gauge oil line. installed it and made sure I didn't kink it. Same thing when I prime the engine I get lots of oil to the start of the copper line but just little drops of oil to the oil gauge and the gauge only reads 5-10 psi. Also have not seen oil get to the rocker arms yet. priming clockwise and turned the engine over slow clockwise. Is there something I am missing? Do I just need to prime it longer? I have primed it for about 6-8 minutes. so much that my drill starts to heat up really hot so I stop to let it cool down. Other have said it take a couple of minutes, so I feel like it should be showing oil pressure at least by now. Thank in advance for any help.


So lets start at the beginning. What was done to the engine while it was out of the car? Did you use the same oil gauge setup before to check oil pressure before you removed the engine?