Dr.diff brake converson

Here. I marked them for you.
View attachment 1715977858
"15/16" Bore w/4 Hole mount for all A bodies" (or choose the 1 1/32" master if you want. Both are listed "for all A bodies"- depends on the pedal feel you prefer)
"Add front disc/rear drum brake combination valve"
Actually, I believe he wants to make it manual disc. In that case, he would need to check the lower dot in the master cylinder section.