You asked for gurus, but I'm not one.. I'd call a converter company and see what they recommend. You'll want something that doesn't slip much at highway rpm, so your anticipated cruise speed and gear will matter a LOT. Even then, you may not be happy on the first try..
For a truck, depending on what kind of tires you run, I'd be looking at 3.55 to 3.91s. But you're in Texas where speed limits aren't as oppressive as many places.. So you may want to try less gear, but that will tighten the window of operation some.
BTW, if you had more stroke and compression, it would be a different story...
