4.88 or 5.29 Keep the backlash tight and make sure you have plenty of preload on the carrier bearings.
Also make sure they are V6, not 4 cyl housings.
I just got back from beating the crap out of mine with 4.88's and no problem yet.
2nd gear hole shots in some thick ass mud locked with my 3.0L TD and 38's.
Who made the 5.71's? Hope it wasn't Geniune Gear? They are the worst. I couldn't even tighten the ring gear bolts without stripping them.
Good luck,
Mark