...so I've still been chasing the 'engine chatter' issue, and I've had a lot of updates since the last/above reply in this thread, and I didn't want to belabor this thread when the other has the follow-up, and the bottom line is I apparently had way too much lifter preload, and a set of Melling MPR-667 measuring 6.792" appear to be the ticket...at least for this engine. This should be the direct link -

https://board.moparts.org/ubbthread...ng-magnum-lifters-or-no.html#Post3209569

- Sam


71 Demon (project): 318, A-833od, 8-3/4, 3.23's
14 Wrangler JKU M-380 "Kilroy" (under construction): Magnum 360, 46rh, Atlas4, D60/14b-5.38s-Grizzlys, 40s
07 Ram 3500 MegaDually 4x4 "Big Mack": 5.9 6BT, G56 'Toy Hauler'
52 Willys M-38 "Poncho"