MARK , It sounds like an oil passage plug has backed out somewhere , not sure how a mopar is made , but on some ford blocks there is a small freeze plug in lifter valley in an oil galley , had one come out and lose pressure , after I wrestled with oil pan to change pump , I removed intake and found the plug out ( lucked out ) , does mopar have any plugs behind timing gears??? if it was like that before then it has to be an open somehere since you changed everything else ...