Just curious, could a disc/drum MC be used? The one chamber would be larger but would that be a problem? If it could be used that would save buying another one when doing the disc conversion.
Also on Manual and Power differences, it seems that most of the Power MCs have a very short pushrod chamber and the Manual MCs have one that is a lot deeper.
There are cautions about using a Power MC in place of a Manual - on the firewall - due to the chamber being short and the pushrod could fall off.
I'm guessing it is because most that have power brakes have the MC in the front of the booster. That is opposite some of the TBirds (all 55-57) and some of the Square Birds (Under dash booster I think - need others input on that) which have the booster after the MC.