A-body axles

I have an 8-3/4" rear in my 67 Valiant. I moved the springs in .800" to help clear the bigger tires. The axles have the 5 on 4" pattern. I can get a set of 5 on 4-1/2" axles on ebay for bigger rims and tires later. I have a rotary table for my mill so redrilling the drums is not an issue. The drums are 10". Will I have to do any other mods to make this work? The rims are 8-1/2 X 15s now. I want the bigger bolt pattern so I can go with at least a 10" wide rim.