i always refer to issues like yours as "bleeders:.i've built them before and never found a comfort with them. there could be a multitude of small things that can contribute to this but in my experience the majority "bleeding" is in the bearings (rods and mains). there could be a cam bearing issue and i'm sure edm tappets don't help matters but i doubt the main cause. my opinion is if your going as far as pan removal then go the extra step and get the engine out on a stand. it's the only sane way to diagnose the issue and solve it.
I tend to agree with the above for several reasons. #1 it's going the be a lot easier on a stand. #2 the lack of metal in the filters indicates it's likely not a wear problem. #3 You can prime the motor on the stand & check the readings before re installation.
If you had taken the readings by running the pump with a
corded electric drill before dropping the pan you would have a reference point. Possibly you still can by just bolting the pan back up and putting the oil back in. It's not going to make a mess as the motor will not be running, just circulating the oil and it will be a very VALUABLE reference point. Might even be worthwhile to pull the plugs and have a helper slowly rotate the motor 4 complete revolutions while watching the gauge for any variation
Your previous readings (before the oil & filter change) were not all that impressive IMO. I have zero experience with the EDM lifters so I cannot offer any advise there but perhaps the supplier of the lifters can. how much lift does the cam have? I have read of a few instances where an excess amount of lift raised the "oiling" band above the lifter bore. Anther thing to check would be the lifter to bore clearance. Good luck and do keep us posted
