Matton you seem like a good person so this is my advice...sell it to the next sucker while you still have the chance... once these 5 speeds start breaking (and they will) in a few years you likely won’t be able to get parts ... and it will be more worthless than it is currently.
Put a TKO, T56, T5 or gear vendors in the car and your great grandchildren will still be able to get parts for it barring any cataclysmic world event.