Rear brake question

I have a 71 duster with the 8 3/4. It has the wonderful 4 inch bolt pattern. I am going to be switching axles for the 4 1/2 bolt pattern. What do I do as far as brake drums are concerned? I just replaced all the brake shoes,wheel cylinders, and hardware, so I was hoping to not have to replace all of that stuff again. Let me know what all of you are doing on a conversion for this thing. I am about sick of this stupid four inch bolt pattern!