Warren
If you have an air shift transfer case (you should, in a '75), there is no advantage in removing the shaft instead of unlocking the front hubs. You can install Selectros, ($550 a pair or so), or you can get a spare set of front drive flanges and having the splines machined out. That has the same effect as putting on Selectros, just cheaper. Selectros, however, are easier and quicker to lock and unlock, rather than changing drive flanges.
The advantages of freewheeling hubs (however you do it) are:
1) Less parasitic drag from turning all the axles and gears in the front diff., plus the front drive shaft.
2) Less wear on said front diff. and drive shaft.
3) Somewhat improved steering response.
4) On long road trips, you should see a slight improvement in fuel economy.
I am running a set of desplined flanges on my deuce. Eventually, when my ship comes in, I am upgrading to Selectros.
Another mod that has been discussed in detail in the past is pulling one rear axle shaft. You put a front drive flange on in its place. this really improves turning in town.