"I LOVE THE SMELL OF BURNED CLUTCH IN THE MORNING"
You said, that you do a lot of towing and hauling. In the real world, you never back into or pull out of a spot that is level when you have a load.
Either forget the 3.08's or forget the 3spd. 3.23 or 3.08 would be fine with a truck 4 spd such as a '68 up SM465.
That means you are changing engine, trans and rear. You could keep the 3.73's, use a 4spd OverDrive like ftyler and truckedup are using or go to a T5 like mugsy is getting ready to do. That way you only have two things to change.
