If you're running a loaded 2 ton without a Hydrovac booster, you're a hazard to yourself, and everyone who shares the road with you. In order to convert to a dual chamber master cylinder and do it properly, I'd suggest looking into a system that Winnebago used on some of its motorhomes, which incorporated a dual chamber MC and two remote vacuum boosters, one for each axle. Swapping to the entire dual brake setup, including the twin boosters, from a retired motorhome would allow you to take advantage of pre-existing engineering, and make the installation as safe as possible. The only advantage of a dual chamber MC over the single unit your truck was engineered for is the redundancy of having half a brake system if a line or a wheel cylinder fails on one axle. Use ALL the associated components of a dual system, such as proportioning valves, lines, booster(s), etc. not just the master cylinder. The system needs to be able to isolate a failed part in case of a problem, and still retain partial braking.
Jerry
