I bought a 01 FL70 5yrs ago & it has the ICS electronic version of the 8.3 & it came w/a 4.11 gear that I changed to 3.42 since,the changed 70mpg from 2450 to 2000, I usually run 63mph & 1700 rpm getting over 10mpg.I also have a tall box 13'6" which kills the mpg the faster I go.Best cruising...