325's are around 36 inches. You will need to do a spring over conversion, or probably a 4 inch suspension and 2 inch body lift. Running 36's you will need at least a new rear axle, like a Ford 8.8 or D44. The front D30 can handle it if you dont do a lot of hardcore stuff. Then you will probably have to regear. Your might want to trade the tires for some smaller ones, get a 2-4 inch lift, and sell those wheels to a hood rat.