I have a 76 master on my 76 disk/drum stock setup. Haven’t driven it yet. 😂😂
On my 78 I have a disk/disk master from a non abs 80-series and it’s perfect. I did the GM caliper conversion on the back so it does have disks all around. I added a Willwood proportioning valve for the rear balance...
Definitely consider swapping the master cylinder to a disk/drum unit (rock auto is where I got mine) the reason is drum brake cylinders have very different pressure/volume requirements than calipers do. It will be difficult to safely balance them with a drum/drum master.
1976 fj40 brake master...