I put a master cylinder and booster from a 76 in my 64. If yours is from the same era it should be the same.
For the most part it did bolt in rather easy.
I had to drill a couple of extra holes in the firewall to get the booster mounting bracket to install (not a big deal as a couple did line up). I believe that I got 4 of the 6. The other 2 were left unused. I also had to trim the steering column bracket clamping point to clear the new power boost bracket.
The hardest part was to make an adapter for the rod that connects to the brake pedal. The newer master cylinder used a different hookup to the master cylinder so I just used the half from to the 76 master cylinder and the half from the 64 brake pedal. Make an adapter and the two will join.
After that I added a late model proportioning valve.
I used it that way for 5 or 6 years. I am now doing a restoration and will most likely put the proper one in (will cost a bit though).
