Inliners International Forums General Discussion Drive Train Chevy II rear ends

I have a 63 Chevy II I would like to put a Posi and lower gears in. I seem to recall that the pumpkin in the early Chevy IIs was the same as 55-64 full size Chevies. Is this true? Can I take a Posi from a 55-64 full size Chevy and install it in my housing? What about axles - I currently have 4 lugs.