New Rear-end

I believe your car is currently has a /6 motor and a floor shifted 3 speed transmission. If your planning on upgrading to a V8 you might consider an 8 ¼ from a Junk Yard A Body donor vehicle otherwise, 7 ¼ should be sufficient. I have had a lot of luck with junk yard rear ends because the gears can be inspected easily and there fairly cheep.