January 9th, 2012.
Like a Boss:
While it is your truck, many of the modifications suggested here above are,beyond the changing of the engine, the usual "Jack Leg: engineering as regards designing a brake system modification to the deuce. It wasn't designed to go past 45 normally, especially in the M35A1 and A2 series (and the A3 is not supposed to be driven faster then that), as it was a "Tactical" truck, not a road truck, they are two different beasts.
You may profit by splitting the system using -A3 components, but any home designed modifications subjects the the designer and truck owner to the potential for cancellation of their insurance should the system fail at any time. Should you survive the wreck, you probably won't have a legal leg to stand on. The conversion of M35A1 to A2 status is straight forward, but the truck's still not going to do 60, and with the brakes as they were designed in 1948, stopping under load is iffy. Increase the tire diameter, gain a few MPH, lose the torque that might just get you unstuck....
It may be you have the wrong truck for your need for speed, trade it in for a Unimog U1300L with Ultra High speed axles and you will have a better truck for your needs.....
Just a thought, take it for what it's worth, as I haven't seen any licensed engineers on here propsing to produce the upgrade compents and assume the liabilities thus created....