Misfire around that engine speed (with the work and exclusions you've already done) make a very unpalatable thing likely.
You may have a flat camshaft.
Roller lifters on the Hemi engines are starting to fail at a rate that's above average. Pin (roller) bearings inside the outer roller bearing surface dissolve or get spit out, causing the lifter to have erratic action. Valves get held open at higher engine speeds, dropping compression and causing this sort of problem.
Have you noticed a clicking noise that gets louder with RPM? Sometimes this happens and when it does, it's a pretty good indication of valve lift issues. I've seen others with flat lifters that never make noise, but if you hear it... it's another nail.
Compression testing of the cylinder -- statically, running (at idle) and under higher speeds-loads -- are the best way to sort out this sort of thing. Cranking compression will likely be good, as will idle (not much demand for lift on these engine speeds) but things will fall apart at around 3K. Compare your 3K reading to another (good) cylinder under identical circumstances to tell what's going on. Compression testers vary so much that I no longer use hard numbers to determine engine health -- I prefer to compare good holes to bad. Using the same tester, differences are more obvious an valid.
Check it out and listen. Let me know if you have any questions or problems and I'll be glad to help. I'm at the shop tomorrow, but will watch for your post.