IMHO, for a 4x4 I'd stay with the G54. Longer stroke and bigger bore = more torque. If ya got a DD, mebbe think about sending the short block in for bore and balance at the least over a 63 drop? Yeah, it ain't a racecar, but you could make it that way some day if you wanted to go injected/turbo route.

Never had mine dyno'd, but I thought stock G54B Hp was 105? Could be wrong...

Possible the LSD just needs a rebuild? Not that hard nor expensive as I recall. Other than yanking it outa the pumpkin, that is.