4.10 to 3.08-possible?
 

I have a 04 F150/XLT/SCAB/4X2/LBOX with the 5.4. It has 4.1 gears with a limited slip. I would like change the rear end gears as I mostly do highway driving, my payload is not heavy and I never tow. I think it has a 10.25" rear end.
-what's the lowest final drive I can put in it, is it 3.08?
-will I be able to keep my LSD?
-how do I re-calibrate speedo/odometer?
thanks