Hi, when I went to install the power booster in my 67 Mustang, it had a manual MC. I had to enlarge the hole for the power booster to fit and drill holes for the booster as well. It was a factory replacement booster from Chockstang. I don't know if your year would have that problem of having to enlarge the hole for the booster to fit.
I did install front disc brakes, so I needed a proportioning valve, so I used the ssbc adjustable proportioning valve.
However, I had my engine out doing the restoration process and was able to have plenty of room to work.
Do you have 4 wheel drum or disc drum?
You can make out where the old MC went, imagine the booster fitting up there. Wish I had know before paint work
