Either way you still have to buy parts. Your stock MC will not work with disc brakes so you will need to factor that cost into the conversion. There are lots of parts available out there either to restore the drum brake system or convert to disc brakes. You should be able to get a good deal on some take off drums from someone that converted to disc's. Brake shoes, cylinders, and hoses are relatively cheap. Do an analysis of what it will cost to rebuild the stock system or to convert to disc's. Take into account that some of the disc brake systems cannot be used with stock wheels. lots of things to consider.
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