Well, after talking to ORD and taking a few more measurements, I decided I am going to start with a 2.5" shackel flip in the rear and see how things are at that point. This will let me get out and test some flex and see if there is any other clearance issues. I can then go from there. I would like to keep this as low as I can as it's already got a higher CG then a typical truck. I think in my overall plans, I will manage to keep the CG low by keeping most of the heavy stuff low in the box or on the chassis. The box A/C is coming off so that will get a big chunk off.
Guess I'll need to wait for my parts to come in...