Rear Brake question

The 9inch brakes are quite a nice thing.... less breaking at the rear provides a better bias for disks on the front
although the aussie cars do all benefit still from a brake bias, to allow the front line pressure to be high enough to get the calipers to actually work properly, without the rears locking first.
9 inch brakes at the back with the small bore wheel cylinders works well.

aussie car had a lighter rear end in most cases 7.8 inch BW rather than 8 1/4 or 8 3/4 mopar, potentally why 9 inch drums stayed after 1971