A 4.10 ina 450 will have the SAME pulling power as a 250 or 350 with 4.10's. AS ALL three have the same tire diam. Granted not rim diam, but the tire diam is 31.5-31.75 for ALL of Fords 250-550 trucks. So reality is, gear ratios in the lower, ie 4.88 range will use more fuel. BUT< they do give you more low end grunt to go up steeper initial grades. From a speed perspective, no difference, as that is limited by the HP of the motor, as long as the gear ratio choosen allows the motor to run at is highest HP for the speed. Then it is possible that a 3.73 could be the best ratio!
Would I change out? How much would it cost? and how long will it take to make up the fuel savings? if over 100K miles, and 3 yrs, too much initial cost.
Marty
