I''ve never seen that on a 360.
As I interpret your picture, it is looking down the distributor hole while driving the oil pump with a priming tool. Oil is spraying out of the plug and going onto the drive gear.
As far as I know the plug at the end of the lifter galley is solid with no hole? Where did you get yours? Or did you drill it yourself?
I always thought that the drive gear was oiled from the overflow from the lifter valley spilling onto it. I just looked at my block and I can see a path where the oil from the head should go down to the drive gear.
Would the hole in the plug lower the pressure to the rest of the oil system above it?
It looks like a good idea to have the hole, to make sure that the drive gear is lubricated, if it doesn't sacrifice oil pressure.
However, I've never seen or heard of a problem with the drive gear oiling.