Was 6 inch with 37's, now has 33's and looks pretty funny on 6 inch springs. If he can't get custom I'll probably go stock with 2 inch blocks, not the way I've ever lifted a truck before (or lowered in this case) but it will ride softer and be level.
2" blocks won't be an issue at all.. when we used to run 44's we would use 4" blocks and big *** springs... i don't miss doing trucks.. those tires are heavy :)