Better yet, drop that rear hanger..
My old confer shackles were pretty long though, possibly that long. Another options is to use an anti-wrap bar. If you can ditch the blocks do it though! Then worry about the height in other ways such as an add a leaf, different springs, or possibly a rear johnny joint welded to the frame as a rear hanger. That will drop it down and allow the spring to twist without destroying your bushings.
Making shackles is pretty easy though, go to the steel place and get some 2" x .5" flat stock. drill the holes and cut one. I use a big washer as a template for making it round by grinder or whatever. Then use that one as a template for the other 3.