la 360 rocker arm oiling

The groove around the number 2 bearing will indeed constantly oil the driver's side rockers and over oil them. I would surely get that one out out and replaced for street use. It would oil at any crank angle. It will also pull some small amount of oil away from the #2 main bearing and the #2 and #3 rod bearings; that may not matter.

The #4 cam bearing has the holes to oil the passenger side. If the holes are there, then you have to be close to the right crank angle to line to holes up.

BTW, the angles shown above are for a stock cam. Many aftermarket cams will have it set up that way, but some won't. I just found out that my new Crane Cam had to be 45 crank degrees earlier than the numbers above to line up the cam oiling holes. So you may have to hunt for at least one position.

The passenger side lifter gallery is actually the main feed into the engine from the filter. There is a passage from the front end of that gallery down to the #1 main, where it feeds the main and #1 rod, #1 cam bearing, and another passage from there back up to the front end of the drivers side lifter gallery. The driver's side lifters are all that is fed from that gallery.

As for the lifters, if you pull any one, you will see a hole in the side of the lifter bore into the lifter galleries; this hole is normally 1/4" to 1/2" wide. The lifters have a 'waist band' that overlaps that lifter bore's hole into the lifter gallery, and the oil gets in there (at least at zero lift) to pressurize the lifter piston. If they are not being pressurized, then:
1) The lifters may be wrong
2) Some one may have closed off the holes in the bores with a tube and peen process, where a copper tube is driven through the length of each lifter galley, and then the copper tube's side peened down in each bore with a tool to allow the lifter to be reinserted in its bore. This can be done for mechanical lifter setups. So pull a lifter and see if the side of a copper tube is visible.

Is the air coming from around the lifter bodies or from where? Small bubbles will come out for a while around the lifter bodies when you first prime it, I suppose from the filter being purged and air being purged from other places.