I just swapped cams in my 400 and it runs great. Your cam is installed correctly, no question. The outer ring on your harmonic balancer has probably slipped on you. Common problem. If so it's trash, get a new one. If you use a piston stop and find zero tdc and your dampner doesn't line up to zero tdc, then your dampner ring has slipped or your timing pointer is attached in the wrong place on your front cover.