I copied the info below from a 2015 post I did to help solve the exact problem you are working on.
Prior to 1963/4 (depending on the engine), Pontiac engines oiled the rocker arm balls and the rocker arm tip to top of the valve interface by pumping oil through a passage from about 2 o'clock on the #4 cam bearing to the left head and a passage at about 10 o'clock on the #2 cam bearing to the right head. Oil is "timed" through the cam journal as the cam turns. This means that the oil only gets to pass through the cam during a few degrees of cam rotation.
Once the oil passes through the cam it travels up a passage in the block to the head and into a gallery that runs front to back (or back to front) in the head. The bottom of the rocker arm studs sit in this gallery. The stud has a small (about 1/16") hole drilled up the center of the stud, almost, but not quite to the top. Another hole is drilled through the side of the stud, just below the threaded end, meeting the hole up the middle of the stud. Oil passes out of the stud and lubricates the ball/rocker and rocker/valve interfaces.
The rocker/pushrod interface is lubricated in the familiar way, oil being pumped from the lifter and through the pushrod to the rocker.
A picture of all of this can be found in this GMC (they used Pontiac V8 engines from 1955 through 1959) Maintenance Manual.
http://chevy.oldcarmanualproject.com...5559mm435.html
So the net of all this is that you can't expect oil to reach the rockers in an old Pontiac V8 unless you have the camshaft in exactly the right rotational position. And both heads will not get oil at the same cam position.
... and all this assumes you have the proper 3 holes drilled in the #2 and #4 cam journals and bearings with matching holes and that the bearings are aligned with the holes in the block. The holes in the bearings are not evenly spaced.