Go check out
http://www.mpbrakes.com/MP11.HTM They have pretty much anything and everything you need for any combination. Very good site for information as well. For my 65 I just went to a disc/drum combination and used a 74 Maverick dual master cylinder. You can find NEW (not rebuilts) at
www.greensalescompany.com 1 15/16 bore, so its the same as the single. Very easy swap. Large chamber always goes to the front and small chamber to the rear. Because of the 4 piston calipers on the discs, they need more fluid. Took me 15 minutes to do the swap.
Ron