6.4 water jacket, with a lot of Iron to machine around the 1st cam journal.



As for the Lifter argument , lack of oiling is part of the issue, the other is the VVT it's self, computer programing. there's a lot to it, kind of like a perfect storm deal....one of the dealer mechanics I know who's done a few was showing me one 2500 where the issue was the lifter yoke cracked, the other one that stood out to him was a 2011 Manual Challenger , that had MDS lifters in a non-MDS engine...bad valve springs was part of the earlier issue, wrong springs ,

FCA/Stellantis has done a enough spintron testing to know what the problem is and how to fix it ...but they can't it's an Emissions function device and you can't remove them, you can only add to them.