shackle flip question

[doug70]

I want to lift my 71 k20 about 2-3 inches. I am considering the shackle flip for the rear. I have an extra front support, can I just use it for the rear? My replacement springs are from an 81 1 ton(56"). Do I just install the hanger 4" further back than stock? I have read some about this, but would like some good definition of the benefits and drawbacks.

I really want to get rid of the camel backs in the front. What trucks use the same length spring. I have access to lots of old trucks.

The truck is being converted to dually. 60/40 onroad/offroad. Some of the ruts where I go are deep so some extra flex would be nice but I drive highway too and want a safe ride.

Any suggestions welcome.

Doug

[doug70]

picture of dually.