56" springs for rear with 2" lift?

[6768chevylover]

I Installed 2" tuff country EZ springs in the front of my 71 blazer but still have the stock 52" springs on the rear with an add a leaf to level it. I would like to put a 56" spring in the rear to give a softer ride but don t want to do a 4" lift with a shackle flip like most of the threads out there. I would like to get a 2"-3" lift out of the 56" spring. How would I do this? I have no clue if mounts need to be moved or if I need longer shackles or etc? would appreciate any advice.. Thanks, Mike