Small Block Oil Pump Priming

Saturday I picked up a piece of 5/16 hex rod so I could prime the oil pump on my magnum headed 360.

I have a couple of questions;

1. I put a pressure gauge in the oil sender port next to the distributor and I was only able to get 10 psi with a 1/2" electric drill. Is this to be expected? The drill did slow down once the pump started picking up oil.

2. I hand turned over the engine in 90 degree increments as I was doing this and I was able to get the right side lifters to pump up and got oil up the push rods to the rockers (remember magnum heads) but not the left side. Once the oil flowed to the right side shouldn't it have gone to the left side too? Could I have missed a oil galley plug? I installed threaded plugs on either side of the cam at the back of the engine and pressed in small freeze plugs on either side of the cam up front. I also installed a threaded plug under the oil filter plate.

Any words of wisdom or am I OK with what I saw?