Per the U-bolts i can get the torque later tonight when i get home from work if nobody chimes in.. But if you have time try searching in this thread for a PDF copy of the service manual.
http://67-72chevytrucks.com/vboard/s...d.php?t=558016
And per the shocks that's the same trouble i have been sorting out, just be sure not to ding them up so they are returnable.
If you have not already, after you remove the shocks and with wheels on the ground get a measurement on level ground from eye bolt to eye bolt, that's the static sag, then jack up the truck off the wheels and get that measurement that's fully extended dimension.
The formula is posted on my thread to find the remaining usable compression:
http://67-72chevytrucks.com/vboard/s...38#post6389138
I really don't know why the drive lines would be different unless they have a manual verses auto tranny or a different transfer case.. So the splines are just to tight to swap the slip yokes? I wonder if its just the diameter of the slip shaft or if its the splines? If its the diameter maybe you could just sand it down a little..