66 B body 8 3/4 to 72 A body swap

So I have the exact same plan for use in a 72 duster. I used a 66 model year 8 3/4 to get the big bolt pattern.
Your only concern is that the valiant doesn’t have the wheel space a duster does.
The extra inch of axle width (at the axle flange) can be corrected with wheels.

Are you making any brake changes?