My front disc brakes came from a 1975 Comet. A friend gave me everything for free. The master cylinder is from a '74 Maverick, and is not power brakes. All of the front brake lines are also from a '74. They are a direct "bolt on". '75'-'77 front brakes lines will require modification. In '74, the M/C was the same for Disk/Drum and for Drum/Drum. There was no proportioning valve (although it's a good idea to have one). You need the Spindles, Calipers, front Lines, Hoses, and Rotors (as well as new pads, and new wheel bearings & seals). As mentioned previously, Granada discs are the same as Mavericks. Also as mentioned previously, the correct outer tie-rod ends "may" be required. Some had a longer shaft than others, depending on when the car was manufactured. I doubt this will be an issue on a 1974 model.
