A real head scratcher !!

[Chamberpains]

Like Starlight said it sounds like s Cam's might be different. Rawze is right on measuring things. You've already ruled out the hard way that the shoes in the drum go together. Now try the easy way and get your tape measure out and sing that Sesame Street jingle "one of these things is not like the other."
If you haven't owned this vehicle its entire life and know what parts you put on it. It's very possible someone else screwed up and slid in the wrong Parts sometime in its life.