my k20 has 52" springs in the rear, but they are shot big time (1 leaf on driver side is broke and sags 2" lower than the pass side.) next weekend im getting rid of the blocks and putting a good set of springs in the rear along with a home made shackle flip. i have a very good set of 3/4 ton 52" springs, and i bought a 86 k20 chassis with a good set of 3/4 ton 56" springs. i like the flex that i have with the 52", but also the load carrying capacity of the large pack 56". its nothing to pop the rivits off and move the hanger back 4". should i run the 52s or the 56s. any help would be apreciated.