Is it the polyolester, not he moly, that quiets the Hemy tick down?
My (non-professional) theory is that the oil pressure at idle is too low for these engines once the oil is warmed up. Today, on a not-really-hot day (69 degrees) after 15 minutes of driving I was at 31 psi idle pressure. I know technically its fine, [censored] Chrysler says 5 psi at idle is OK, but I feel like the top end doesnt get enough lubrication at ~30 psi. Just getting the engine a hundred or two RPM off idle brings pressure up to 40.
Why does this matter? Moly will plate the parts which I think will help everything stay quiet and as wear-free as possible, FOR A SHORT TIME. Extended idle times of low oil pressure will cause the moly plating to wear away, leading to the noise and presumably wear. Do that enough and you'll end up with a "permanent" ticking noise and who knows how much wear. Redline has a LOT of moly in it, so it could be working better just because there is so much that it "extends" how long you can run "low" oil pressure before it becomes an issue.
I think the thicker oil helps because it stays thicker when hot (could be proven just by watching the idle oil pressure between different oils). Get a 5W-30 with some moly and you should be good to go. So, something like PP 5W-30, PUP 5W-30, etc should be OK too, not just Redline. The Pennzoil products have the chrysler "spec" but -30 isnt spec-ed for the 5.7L Hemi in a RAM 1500. My truck has 3500 miles on it, is pretty quiet at idle running the dealers free oil (which, if their invoice can be believed, is PYB 5W-20) but I only have about 1000 miles on the oil. After 2K miles on the factory fill the engine started to sound louder at idle, but it was also during the winter as well.