small bolt pattern to big bolt pattern

I have manual bbp a body disc brakes on my Dart Sport, check out my build thread.
They are definitely stiffer with more pedal effort than power brakes, but they are not too bad at all.
I have a '69 Valiant with the same set up and they are the same as the Dart Sport as far as feel and function go.
Power brakes were an option on '73 and newer V8 a bodies except 360 cars ('74 and up) and 340 cars ('73 only) which were standard equipment. If you ordered power brakes on a '73 and up a body, you automatically got the good bbp disc brakes up front and bbp rear end with the bigger rear brakes, even if it was a slant six car. Manual brake slant six cars always had sbp 9'' drum brakes.
After Jan 1st 1976, all a bodies had bbp disc brakes on them and bbp rear ends of course.
Bbp rear ends came in 7 1/4'' or 8 1/4'' in these years ('73 and up), but the 8 1/4'' rear end came standard on 340 and 360 cars. Sure grip was optional on all cars.
In my opinion, the a body cars '73 and up were much better in the braking and steering department than '72 and older cars. Heavier duty.
And parts for them are easier to come by and cheaper to boot, a win win situation......
This is some info if you are looking for a donor car or wanting to make an upgrade.