Originally Posted by 52 Merc

Welcome to the forum, Rick! It sounds like you've got an interesting project on your hands. Changing the m/c out to a dual reservoir is not difficult, and for the obvious reasons you're already aware of, it's a highly recommended modification. The hard part will be finding one compatible with your large truck brakes. I don't have a clue on what to recommend for your application.

Especially if Bill is correct about the stock master having either a 10 inch or 12 3/4 inch piston bore.