You're going from a 30" to a 35" tall tire. You'll need a suspension kit and a lift kit, along with new shocks and eventually new ball joints, new idler arm, lower rear end gear change and electronic speedometer kit.
I run a 285/75/R16 with a Trailmaster 4" suspension kit and Rancho 9000 air adjust shocks. I've replaced the idler arm 4 times in the last 10 years. I've even got a dual steering dampener and all new bushings, but it still keeps going bad.
The Expeditions were NOT designed to be lifted. I'm not saying it can't be done, just be prepared to spend some money to do it right if you decide to go that route. Just don't think you can throw on a three inch body lift kit and some big tires and wheels and head on down the road without any problems.