Hi there. I am new to this forum, and looking forward to hearing back from all you experts out there.
I recently purchased a 65 coupe that I am working on restoring as a daily driver. I had a probelm with my brake pedal going all the way to the floor when applying the brakes. I have front disk conversion and rear drums.

I bled the brakes, but that did not help. I took the car to a brake place, and they recommended I change the master cylinder, so I did. I was told that the master is off a Ford Ranchero 1976-78.
The good news is that the pedal is higher, the bad news is that now the front brakes are sticking at various times. The car can go along fine for a while, then one or both of the fronts stick.

Obviously something has gone awry. Any help/advice would be much appreciated.  

While it may be a master that not fully relieving. Most likely, its the fact that your brake calipers may be your issue as well. After a while the piston doesn't move freely and sticks (usually due to corrosion). take the calipers off and rebuild them. be sure to look fo rany signs of pitting on the pistons and replace tehm if not removable. Dont worry about pitting in the caliper if the piston makes good contact with the seals. (it's the seals and piston that do the work not the housing)