When I did my Granada swap I bought an adjustable pushrod from Mustangs Plus for $40, plus $8 shipping and handling. If I had it to do again I would take more time and do the following.
1. Buy the MC from Autozone or where ever.
2. Install it in the car with the pushrod that comes with it.
3. Measure the location of the end of the pushrod on the brake pedal.
4. Remove the MC. DON'T DEPRESS THE BRAKE PEDAL HERE!
5. Measure the location of the end of the pushrod on the brake pedal fully depressed.
If the travel is too much for the MC, you need a shorter pushrod. Make sure you check the travel before depressing the brake pedal with the MC installed. If the travel is too much, you will damage your brand new MC!!
I have front discs and rear drums, and I'm using a '77 Monarch MC. You will want a MC from a car that had front and rear discs, since the discs need more volume of brake fluid than drums.
Also, when you're bench bleeding the MC before the final install, the bench bleed should only take 5 minutes or so. I bought 2 defective MCs before I finally got one that worked. Since it was my first time doing this conversion, I wasted hours figuring out that it was bad MCs, not something I was doing wrong.
