Another Can I do it

I am considering putting on aftermarket wheels for some extra rear width. I have a 73 Dart sport with an 8 3/4 B body rear end. Not sure if it matters but it was the one where I only had to move the perches 1/2" on each side. I was hoping to run 9" wheels. Can I get them in the wheel wells without moving my springs or hacking up my fenders? If so, what backspacing do I need?