FZJ in USA
I've removed the front prop shaft on my 96 (now gone) FZJ (petrol) 80. I added in free wheeling hubs on the front.
Driving takes a little bit of getting used to (as now rear wheel drive) with CDL.
For me only worth running when no 4x4/camping events planned for some time or on long journeys (and when petrol prices are high)
I gained about 2 mph on long journeys
Have a 97 now and not done the mod (petrol prices here approx $4/gallon and may consider doing LPG conversion as $1.5/gal- had it on my 96) - here in Seattle, USA. Prices not high enough unless going on long journey and no off-roading.
To gain mpg - get rid of any excess weight (tools , extra 3rd row), heavy sliders, front/rear (if heavy) bullbars/tire carriers and any roof-racks. Also up the psi in your tires. That gains me 1-2 mph on long journeys (but hard to give up the 4x4 'bling')
Lal