I used 2.5" drop shackles and removed the overload leaves on my 1972 GMC. Getting the drop shackles in the upper pockets was a biotch...
One of these days I'm swapping out my bent 1972 leaf sprung frame for a nice and straight 1969 coil sprung frame. I will give you the drop shackles if you want them... but... if you plan on doing this soon... I can't guarantee I'll have them out anytime soon.
Gary
Gary