Why are you going spacers instead of springs? With that high of a spacer you are going to get a lot of lateral movement out of the spring. Causing fatige and maybe failure. The other thing is you will have to address the radius arm ange at that height. Your Down travel is going to be seriously limited unless you do a lot to address it. Also, why so much lift? Anything over 3in is not necessary unless you want to run tires bigger than 37's. My guess is that you want 35's which is the largest that the stock axles can handle after you upgrade everything. In that case, use a .5 or max 1in spacer and you will be fine.
2009 King of the Hammers
BUCK Wild Racing
Co-driver: Pat Quirk
Rover Tracks www.rovertracks.com
DJ Safety www.djsafety.com
West Coast Rovers www.westcoastrovers.com
Reel Driveline www.reeldriveline.com
Made it further than half of the other guys, but the Hammers won.