should I change gears or tranny???

I,d change out the 4.10s for some 3.23,s see,n you,ll be doing highway runs.I did this swap last fall in my 73 D.Sport,she,s now a highway girl.On a second not,my truck has 140liter tank(about 35 gallon tank)and gas here is about $6.00 a gallon:angry3:.Consider yourself lucky.LOL.