Serious thing to remember is that you need a long slide joint with long shocks. You can fit a big spacer for big lifts, but long shocks need a long slide.
You might need a Bailey Morris custom, because it is my belief that a d2 double cardan shaft has a reasonably short slip joint.
You will have to clarify this, but if you're going to do something as ridiculous as a 5" spring lift then you might want a quality prop.