Can someone speak to the options for speedometer correction when changing ring & pinion?

I have an '07 F150 Scab 2WD, 5.4, and its at 3.55:1 now. I am leaning toward the Ford 4.10:1, M-4209-J410M.

 

Have your local dealer flash the computer about a hours labor or buy a programmer.

 

the dealer may or may not be able to fix the speedometer. it depends how far it is off. the best thing you can do is go in and ask. if not, a programmer will fix it.

 

One option, use a tuner and adjust. I have an XCAL2 tuned by Troyer. Just swapped 3.73 for 4.56. Speedo was way off, I reflashed to stock, then on an XCAL2, you can enter opt parms and change the pre programmed gear ratio. It was about a 90 second 'fix'.