Bhhammer, I did some digging online and ended up on an old thread right back here on this site.
http://67-72chevytrucks.com/vboard/s...d.php?t=281235. If this link does not work click on new posts and look for "Frame dimensions...67-72 & 73-87" I posted a bump reply on there to revive it for you. If the info there is accurate, and I think it is, then you should have the info your looking for. It was not in the 4X4 section. That's probably why you did not find it.
I hope this helps you.