The challenge is the location of the brake master. If placing it under the floor, it will not be where the original master was and it will be hidden under the floor. I had a 55 here with this problem and the top of the master where you fill it was located under solid floor, so no adding fluid or bleeding. I ended up cutting two holes in the floor to get to it.
I would not install this type of system in my own truck. I would relocate to the firewall if I could... But that presents many challenges in itself..
Lee
