My 67 Fastback is equipped with a positraction rear end. I wasn't really aware of this until towing it home and noticing the obvious 'click, click, click' of it around turns (and no, it's not a broken open-end

- I became most happy when I heard it!
Is positraction the same thing as detroit locker? Neither are the correct term for such ratcheted rear ends on mustang correct?
I seem to recall hearing that positraction mustangs had their exhaust exit in front of the rear axle. While I have never believed this to be true, my car does indeed have its exhaust exit in front of the axle. As the original exhaust hangers are doing just that - hanging unused, I suspect that my car had an original "normal" exhaust.
Can somebody shed some light this? Was what I heard about posi and exhaust totally bunk? Are there any instanced where this was the case?
Thanks,
Aaron