[Edahall]

A 6BT will have more than enough torque in front of a 3.23 or even a 3.08 rear end for what you want to do.

My Suburban listed in my signature is even geared steeper than if you used a 3.08 rear end and it does very well at high speeds. I mainly cruise at 60 mph for best fuel economy but it is definitely more peppy at 75 mph. I'm currently running 265/70/17 tires which are very similar in diameter to the 235/70/19 tires you plan on using. The NV5600 tranny coupled to a gear vendors gives me a final gear ratio of 0.57.