:happy1:OO-ooh boy!
The cost for modding that 9 1/4" to fit the car vs. buying an 8 3/4" might be a toss up...really depends on the availability to your locale. I know 9 1/4"s are still used in the late model trucks, so if you want to pick up a used set of gears on a trac loc diff, you can find them relatively easily...3.55s, 3.73s, 3.92s. But, I don't know how much you'll spend on the axles.