I feel the need to chime in here...have you ever driven one of these old trucks?
I ask because not everyone realizes that these trucks were NOT designed for modern roads, and can't really go over 45mph...they're simply geared too low (for pulling), and the engines don't have the horsepower to go any faster. If you want a highway-worthy truck, you will be looking at, minimum, a rear end or gear swap.
If you're fine with a 45mph top speed, that's fine, but most people aren't.
Just a word to the wise...
Chris