1953 1/2 ton?
3.38 conversion is not available, unless you change the whole rear end (and transmission)
A change of ring and pinion to 3.55 would cost about $800. This allows you to keep the rear end and transmission.
There is an odd overdrive transmission for the torque-tube, but it was made for a car, it is uncommon, and you have to cut the torque-tube and driveshaft.
