All you need are the FMJ brake assemblies, large ball joint upper control arms from 73-76 disc brake A bodies and the lower ball joint for the same application. Instant bolt on.
Plus new front wheels. Then carry 2 spare tires since your front and rear wheels will be different, unless you change to a BBP rear end (most do).
If you pay someone to do the work, or you fairly value your time (most of us don't), it seems more economical to use one of the front disk kits that adapt your existing drum spindles (Scarebird, Wilwood, ...). However, many other questions - is your front end new or does it require a rebuild anyway? Will your existing wheels clear the disk brakes? No 13" wheels will, some 14" will. Check this also for the BBP swap.
You might also consider the factory 4-piston disk setup for your year. A guy near me (Rancho Cordova, CA) advertises a complete, new-looking setup every year or so on ebay for ~$750. I think you still require 14" wheels. I would do that but I am thinking a more clever plan and parts for the 4-pistons are becoming rare. Still, a period correct system might make your car more valuable, though your fender tag won't match.
