383 with zero oil pressure.

The oil filter will not stop pressure. Make sure you have the proper gasket between the pump and block, as well as the little "O" ring on the snout of the pump.

Remove the filter which will remove all "head" pressure against the pump. You should be able to get oil out of the filter mount in a fraction of a second with the drill.

If not, pull the pump off the block, and either immerse in oil and turn, or pour oil into the pump and turn it

Then fill the filter, install, and try to prime. If the pump is primed, you should immediately feel pressure against the drill