1972 k10 rear springs

[Treky67]

Hey guys, first post on here thanks for adding me. I bought my first 1972 k10 about 3 weeks ago. First thing i wanted to do was replace all the springs, bushings and shocks. So naturally the best way was to order and complete lift kit and thats what i did. Now for the problem, my rear springs don't fit. Like not even close, and i can't figure out why my rear springs are so different. The springs i removed from the truck are 56" eye to eye and 3.5" wide at the eye. The new springs are 52" eye to eye and 3" wide at the eye. Every single resource i have read says these trucks only ever came with 52" rear springs. Nothing seems to be modified on the truck. Hangers are all rivetted like factory and frame does not appear to be cut. Any help would be greatly appreciated.