What causes "cam walk"?

I'm not sure. The rest of the cover is still stamped steel. How much did all that roller valve train cost? How much will it cost when the cam pushes so far forward that the lobes run into the sides of the lifters and break the camshaft into several pieces and no tellin what else? I'm not bein smart, I'm just trying to make sense.
I hear ya' man. Like 33IMP said, may be worth a try. I feel for the guy this happened to. My engine is now in the shop for a rebuild. I'm using a solid roller cam & want the setup to live without spending a whole lot more than I've already done.