It's supposed to have been 4". I bought my springs from Alcan when they were in the middle of an ownership transition. I think they were much more than 4", the rear had clearance issues and a few other things. A great company to work with, my experience just had a few hiccups so I don't know for sure how much lift it was.
I called Redhead directly for the box, they had it in to my door in just a few days i believe. That, the borgeson shaft, and ORD crossover is the complete ticket. That 93 drove better than anything i've ever owned. I had a couple older power rams that I would have to rebuild the front end every year. I never had this truck long enough to know how durable this setup is but it was like steering a sports car.