turbo's and gears.......the big debate.

410s and my old 6.0 i got best of 18mpg with ac. that was with the 4l60

I am going with a turbo in the spring and was thinking of 4.10 with a 30 inch tire on a extra cab short bed or would I be better off with the 3.73 i all ready have when I install a locker.