[franken]

Block lifts are generally considered less good and in front considered bad/dangerous. The front looks to me like a 71 or newer D44 w/ open knuckles and disk brakes, as well as the bowed up leaf springs.
Is it open knuckles, disk brakes, etc? You can snap a pic of the diff cover and compare w/ pics on the internet to figure out what it is.

My guess is the rear is stock w/ block lift and helper springs. Are the shocks staggered or on the same side? Id use the technique above to figure out what the rear diff is.

Pretty sure you can look at the body mounts to tell if the frame was swapped.

For spring specs, start w/ leaf width, length (centers), and diameter of bushings.