That car's been there for a while. If it's got small bolt pattern discs you'd better swoop it up. They're worth way more than a big bolt pattern set. You could sell those parts to fund something else, or use them as they'd be correct for your car.
Someone correct me if I'm wrong on the 8 3/4, but since they quit putting them in A-bodies in 72 did they ever make a factory A-body 8 3/4 that was large bolt pattern? I would think all factory A-body 8 3/4 rearends would be small bolt pattern and you have to change the axles.