i have 6 inches of lift thinking of going to 8 besides springs and brake lines what need to be done

 

Nothing. I have an 8inch and the stock brake lines were sufficient, just re-routed them a little.

 

Umm... no

To go from a 6" to an 8" you are going to have to get a new trac-bar drop bracket, a new drop pitman arm, and new sway bar links. You will also (probably) need to lengthen your front shaft, and also possibly get a carrier bearing drop bracket for the rear shaft on some models.

good luck