4-bolt to 2-bolt Master Cylinder conversion on 71 Demon/Dart

I have the doctor diff kit. bolt-on. Some of the other master cylinders have different sized fittings on them. The Dr Diff one in 15/16" is the one I prefer, and I am sure that it's a dakota master cylinder with the bore for the pushrod. machined a bit deeper. You would need this on any late model power brake master cylinder.