I would not change the camshaft, but degree it as I outlined. The cam you have is fine, it's just in the wrong position in the engine. It will ultimately make more power advanced more than a smaller cam would. But you seem dead set on changing it, so go for it.
I'm worried the way the chained was jammed and snapped from the bolts falling out that it could of created a micro fracture on the cam that i cant see.. I'm not sure if I want to risk it.