Stupid timing chain factoid

Another little "factoid" from years ago........I don't remember the details but at some point 289/302 Ferds went from a 'thinner' to a 'thicker' sprocket. A then friend of mine was putting together a 351W for a Bronceroid and went with a 302/289 cam---different firing order, ya know

Anyway he had trouble it went to hell and it turned out the cam was eating it's own lobes and lifters.........because the cam drive combo was allowing the cam to walk forward/ aft

Now I don't remember exactly, but seems to me that there were a few other engines "this is so" Also seems like it might have involved "mixing pieces" in other words not replacing chain and both sprockets.

"They are not gears"