I've seen this. It's usually (but not always) about 2 things. Geometry is off. Again, a centered sweep isn't nearly as important as a narrow sweep pattern.
The other is pushrods bending. Yep. They bend and then unbend. Over and over and over. I've seen some bend as much as .080! We knew how much they were bending because the witness marks on the heads. There was .080 clearance and you could see the rub marks.
Funny thing is, the pushrods were still straight enough to used.
What is happening is all that bending sets up a resonance frequency that does all kinds of wierd things. You see this on every brand of engine, it's not just a Chrysler thing. If you are running a roller it will also cause the rivets on the link bars to break and crap like that.
That's my thoughts. I could be wrong.
