You state that you are going to replace your mc with a disc/drum power unit. That may not work so well. It sounds like you are going to rebuild the drum brakes. The booster/dual mc is a great idea and is a vast improvement but you will need to get a booster/mc combination that was designed for drum brakes.
There are a number of aftermarket suppliers that offer these units.
Fred

Last edited by rfs56trk; 01/27/2012 5:49 PM.

1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine