Hello All!
Firstly, i apologize that i haven’t figured out how to get to my signature.

My questions concern the braking system of a 1967 S1 / 4.2L fhc that i inherited.

I was shocked to discover that the previous owner replaced the Brake Dual Circuit with a Single Circuit, using a universal slave master designed for some Japanese disc-drum equipped car, with a matching Single circuit master cylinder!

Likely an attempt at saving precious bucks and time, since he would have had to import them from halfway around the world.

That said, i intend to bring back the safer Dual circuit system using the proper replacements.

I plan on using the later setup, and using the Slave Cylinder with the booster band lock (and not the earlier “twist & lock” version).

So my question is wether the Master Cylinder from the earlier “twist & lock” booster is the same one used in the later Band type booster? Do they have the same piston bores, piston travel, residual valve arrangement, reaction valve, etc..?

I’m of course concerned about braking safety and performance. My brakes are aftermarket standard sized 2 &1/8” in front and 1& 7/8” rear by Hye-Dra-Cyl.
I look forward to a definitive answer.
Thank You guys!