A friend needs a rear end for his '98 (I think) Arctic Cat.
I found one for a 2000 model.

Does anyone have a parts cross reference guide to know if they are the same?

I answered my own question. Here is a link to all the parts microfiche for arctic cat ATVs

http://www.worldofpowersports.com/oem/fiche/arctic-cat/index.html#1998

http://www.brownsleisureworld.com/frame.cgi?url=http%3A//www.brownsleisureworld.com/Parts/ATV/