8 1/4 rear end questions

I would not be concerned about finding an 245 ratio A body unit. The key here is to find an A body unit that is a serviceable piece. You can always change the gears/differential.

I have not seen anything of use in the scrap yards here in years, but then I live in chicago too, there arent any A bodies in the bone yards. Having said all this - I'd guess 150 $ is what I'd be willing to pay for one.