Ok, so let's deal with one problem at a time. You are not sure whether you are getting oil pressure which could be either the oil pump is shot or the tang for the distributor is not engaging the oil pump. You will, at least in my opinion, be well served by installing an oil pressure gauge if you have not already. Then you will have to decide what direction to go. The easiest may be to bring the motor up to top dead center and remove the hei. Then you will have to look down into the hole for the distributor with a flashlight and see where the receiver for the tang in the oil pump is positioned. Then look at the relative position of the tang on the distributor at no. 1 firing position. Then stick a screwdriver down the shaft and adjust so that when you install the hei the tang lines up with the slot. Loosen up your collar, and install. Might take a couple of tries but you should feel the dristibutor shaft tang drop into the receiver. That should do it.
oil pump.
Now, it you want to check the oil pump independently, you will need a spare stock distributor. Grind off the pin for the gear and drive it out and remove the gear. Gut everything else from inside except for the body and shaft. You now have a pre oiler. Install it, attach a electric drill and spin. Your pressure gauge should come up to pressure while you are spinning.