The booster would likely be the same for both set ups.
It's the master cylinder that would be different. The disc/drum MC has a built in residual valve which is required for the drum system. However, many aftermarket suppliers provide a Corvette MC with all of their applications. In this case you will need a separate residual valve for the rear. They should be available through most suppliers of the other parts. You will probably find that it is unneccesary to change to 4 wheel discs, changing the fronts will be a vast improvement. I installed a dual diaphram booster and dual MC on a 55 one ton and the brakes were super. They have 12" drums but the main weakness is the cheesy stock master cylinder.
Fred


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