I purchased a chrome alternator but the back of the alternator is "clocked" wrong for my application. Can I just remove the 4 bolts holding the case together and rotate the back where I need it or am I gonn screw something up if I do that?

If this will solve your problem you can do it (assuming it's a 10si or 12si-type unit used in the 70s and 80s- can't speak for the CS-130 style units). However- this may mean that the actually mount bolt holes won't line up (where the little bolt-on bracket is inline with the forward part of the casing)- so it may not work in any event.

Street and Performance make a bracket that will convert a 12 o'clock alternator into a 10 o'clock one. Most of their bracketry is setup for a 10. Not sure if that will help in this case or not.

I'll give it a try and let you know how I made out.

Thanks.