One of the problems you are going to have with your shackles/bolts is that the 61-62 GM pickups had torsion bar suspension in lieu of the common 'A'-arm suspension that the '63 and later had. Your truck could be in the 'Donut hole' between the earlier NAPCO'S and later corporate 4x4's. Wm.
"60 up were factory built 4X4, frames not the same between "C" & "K" .
