different motors. different powerbands. bottom line is you need to drive it to understand.now in a idi ford would it be able to as you say overcome the gearing?
IH v-8's like to rev. the powerband for them is higher and spread out farther.
while a 3.55 behind a IH will allow it to make good fuel economy, the gearing does not allow the motor to rev easily. with 4.10's the truck can climb up the side of a building, but fuel economy suffers a little.
A Cummins 6bt makes it's power from 1800-2200 rpm with a stock governor of 2800. you can move the upper limit a little by installing a 3200rpm governor. Still, a Cummins powered truck will bennefit from 3.55's due to where the powerband is at.