I recently converted my 80 to Part time with Marks 4WD kit and Aisin hubs and Im 100% happy with the set up FWIW. I did not do this mod with the hopes or thought of any increase in MPG, I wanted part time 4wd period.
In my past 80 I did not like handling with part time. With my latest set up I found the handling just fine with little difference. For comparison the 2 80's were set up completely different.
I documented my recent return trip from Cruise Moab to Scottsdale AZ. Which FWIW MOAB totally kicked ass
The test vehicle:
1996 FZJ80 127K
OME 850J/863
35" BFG on stock wheels
Stock gears
No roof rack
Polished Safari snorkel
Overall weight of the 80 would be considered light
1st leg
Moab to Flagstaff
325 miles
Avg speed ~46mph
Brief Stopped for 12 pictures
Several burnouts back onto hwy ie: 2WD
1 hard acceleration in sand on side of road ie: 2WD
Little use of AC, windows open
Lots of up and down hills
Went thought Mexican Water verses Mexican Hat, added 2 miles to route but much flatter.
Total Miles 1st leg GPS 325
Gas used 23.389 - cutting it close
Average speed ~46MPH
MPG on 1st leg 13.9MPG
In my past 80 I did not like handling with part time. With my latest set up I found the handling just fine with little difference. For comparison the 2 80's were set up completely different.
I documented my recent return trip from Cruise Moab to Scottsdale AZ. Which FWIW MOAB totally kicked ass
The test vehicle:
1996 FZJ80 127K
OME 850J/863
35" BFG on stock wheels
Stock gears
No roof rack
Polished Safari snorkel
Overall weight of the 80 would be considered light
1st leg
Moab to Flagstaff
325 miles
Avg speed ~46mph
Brief Stopped for 12 pictures
Several burnouts back onto hwy ie: 2WD

1 hard acceleration in sand on side of road ie: 2WD
Little use of AC, windows open
Lots of up and down hills
Went thought Mexican Water verses Mexican Hat, added 2 miles to route but much flatter.
Total Miles 1st leg GPS 325
Gas used 23.389 - cutting it close
Average speed ~46MPH
MPG on 1st leg 13.9MPG