Lug pattern help.
It really depends on how cheap you wanna go. A new set of axles isn't going to break the bank so to say. A quick look on summit yielded this:
http://www.summitracing.com/int/parts/msr-a30-cst-a451/overview/
Now, this is assuming you have an actual A body setup. Which you should with the 4" pattern buttttt weirder things have happened. I'm not sure with these new axles if you can run your current brakes? I would say yes but I'm not a brake man, they always bored me. I do know if you get truck axles and cut em down, you have to use the truck brakes. Which as others have suggested is an option. But honestly for 200 bucks you get nice fresh axles, not to bad really.
EDIT: Also check out this link. Lots of handy info about the 8 3/4 setup -
http://www.mymopar.com/Mopar8_75RearEndGuide.htm