The 4.10 gear ratio is going to get the truck moving faster off the line than the one with 3.73. Also the one with 4.10 gears will get the rpms up higher, faster, getting the turbo to spoolup faster. Then finally, when the truck shifts, the rpms dont drop as far as the one with 3.73's. That will keep the turbo spinning faster.
Faster spin=faster you get boost.