I've ben a opponent of using the Ford type 9 inch due to the increase pinion gear drag compared to a Dana 60 or even a Mopar 8 3/4 or GM 12 bolt.
Buying all after market race parts for them, including the housing, can make them a lot better on that loss
That may not be a valid concern for most street cars but the differences are measurable with a inch lb. torque wrench
Dana 60 last longer under all lot racing with lots of power, their cheaper also