You’ve got it, the master cylinder and an adjustable brake rod should be all you need unless you’re also changing over to disk fronts. Alternatively you could just buy a manual brake rod, but used originals are frequently mislabeled (ask me how I know) so the adjustable takes care of that.
If you’re changing over to front disks as well then you’ll need the new proportioning valve too. Depending on your application you may want an adjustable prop valve. It depends on your brake choices and other upgrades to the car. Factory brakes should be fine with the appropriate factory prop valve. I use the factory disk/drum valve on my cars with factory brakes, I have an adjustable on my Duster but it uses DoctorDiff’s 13” front disk kit and his 11.7” rear disk kit so I wanted to be able to tune the front/rear bias.
That’s easy, the stock power brakes have a soft, vague pedal feel. And the booster takes up a bunch of space under the hood, which is even more important on an early A. That’s before we even talk about how much vacuum his engine is making.
I swap all my power brake mopars over to manual brakes. I use DoctorDiff’s 15/16” bore master cylinder. It gives a heavier pedal than the power brakes, but the pedal effort really isn’t that bad at all. It’s still an easier pedal than the factory manual brakes. And it significantly improves the sensitivity and feel of the brakes, you can be a lot more accurate with your braking.
