'89 roller-cam LA 360 w/Magnum heads - new roller lifters not pumping up

Here's the video. In the video, the new Mellings are on cylinders #6 and #8; the "good" lifters from the passenger's side are distributed in the front of the engine on #2, #4, #1, and #3; and the problematic lifters from the drivers' side are mounted in the #5 and #7 spot:

The video has not been edited - might be a bit confusing. Following is what you're seeing:

1. I show the difference between the Melling straight-up oiling hole, and the 90 degree hole on the engine's existing good lifters.
2. Next, I run the priming rod on the drill. Watch as the front banks (2, 4, 1, 3) oil perfectly with the old good lifters from the passenger's side, the Mellings (6 and 8) barely dribble, and the old "bad" lifters (e.g. driver's side, now only on #5 and #7) leak down almost immediately after pumping up.
3. Since the camshaft isn't turning, I rotate the Melling lifter 90 degrees to mimic the other lifters. Doesn't work.

[ame="https://www.youtube.com/watch?v=wALp_S2rhsc"]YouTube[/ame]

-Kurt