I like the term "easy", just missing "cheap". oh ya, don't forget all of the other parts that go with disc brake changeover.
http://ecihotrodbrakes.com/early_ford_discbrake_conversions.html These guys are the best trust me no bull shit found it was cheaper than buying original stuff
I have ECI on my shoebox. It still has the stock master, but i already have a kit to install a dual master. It does actually work fine with the single pot master, but there's no backup.
Pick up a 1975-1980 Granada master and pedal--two added holes in firewall and it bolted right into my 51 shoebox--also hooked brakes lines --and used the rear end. Bought the whole Granada at auction for $200 with 302 and c-4. I have not put in disc brakes yet.