Master cylinder interchange disc/drum-drum/drum

Sure, but search for all the posts on that. A "correct" p.v. costs ~$75 vs ~$30 for an adjustable one. The "correct" one has a fixed ratio, which may not be optimal for your radial tires, etc. But, adjustable is only helpful if you do adjust it via skid tests in a wet parking lot.

A drum/drum car does not have a p.v., just a distribution block in early cars plus a pressure-imbalance switch in later cars (~1968+). I did re-use my dist. block as a tee for the fronts. Install a p.v. after the imbalance switch.