When I ran into a core shifted cam from RB I found out that only 2 vendors provided cam cores, Engine Power and Crane. I also found out if you bought a shelf grind from Comp you got the Crane core, but if you bought a custom grind you got the EP core. Apparently the problems are/were with the Crane cores. I don't know where the Purple cams come from, but in this day and age there are cams better suited to individual combos than the Mopar grinds.

I tried to find the lengthy thread I had posted dealing with this issue but apparently it's purged from the system. The extensive picture file I have is locked up in a crashed hard drive. Anybody installing a cam should look for core shift issues. The problem is that the lobes don't line up under the lifters correctly. This prevents the lifters from spinning and/or quickly wears off the taper on the lobes. More than likely, this isn't the issue here, but it could be. Unless you know what to look for when installing the cam, the diagnosis would be attributed to wrong oil, lifter rotation, spring pressure etc.