I tangled with the same question a few years ago. In the end I chose to swap out the original 5.14 gear in my 1 ton for a 3.90 from Patricks (
www.patricksantiquecars.com). From my point of view swapping the gears seemed to be the easiest path. I can now hit 75 mph on the highway. The brakes work okay, but in a perfect world I would have upgraded them too.
Good luck.