Early A width?

FWIW, I used the Duster manual disc master cylinder, lines and proportioning valve on my 64 Valiant. All I had to do to make them fit was cut the flare nut off the line going to the rear brakes and flare on one with larger diameter threads. Other than that, it was a bolt on. I retained the front drum brakes for now and it stops just fine. I cannot put the discs on quite yet, as I need to buy tires for my 14" wheels. Gotta save up for those.