How to narrow a rear housing

Im thinking I might want to have the 8 3/4" rear in my 66 Dart narrowed do to clearance issues. I bought new axles from moser back about 15 months ago and havent used them yet. The few questions are: can I cut the splines shorter or would they need to be resplined once cut? Is narrowing something I could do here without buying jigs or special equipment. How do I cut to be sure to keep the flanges straight?
Are there any good threads on this?
Thanks
Rod