1970 Duster Front Brake Conversion Kit for SBP

You could track down a kelsey hayes small bolt brake setup which will work with your upper control arms, but they can be expensive and hard to get parts for.

Another option is to use the dr diff brake kit which converts to an oem style 73-76 brake setup and can be ordered with small bolt rotors. Be warned that not all wheels (14” steelies for example) will clear the calipers.

You will have to change spindles for either, but it’s not a huge deal.

Others can speak to aftermarket retrofit kits, but I have not gone in that direction.