If memory serves me, George used a Mustang master cylinder on his truck.
I designed and build a bracket for my 37 by which I used a Master Power dual master cylinder coupled with the installation of a T-5 five speed manual transmission. I didn't go the disc route on the fronts, but it could be easily been done as there is plenty of room under the floor board. I have even see a small booster used under the floor board.
