Where are you located. It shouldn't be that hard to find 92-93.5 SR in junk yard. You can technically also swap front diff from Montero Sport or Gen 3 with 4.9 ratio but that would involve more mods, you would need new axleshafts, etc. On the plus side you could fit front locker in there after that.

92 SR, 285/75R16 Yoko MT ARB locker GAST compressor AirLift 1000 MM10500 Snorkel custom rear bumper
02 Montero LS died protecting the master
08 PowerWagon (stock!)