Most early V6 thirds like 3.0 have the same bolt patters as the 4 cyl. There are some years that wont match, mostly first gens and recent models, but I couldn't tell you which. If you do find that it wont bolt up, it's very easy to re-drill the flange and as long as you space the holes reasonably you wont weaken the flange. You could also just buy a $35 Marlin tripple drilled flange and never worry about a drive shaft bolting up again...
http://www.marlincrawler.com/htm/diff/pickup_diff.htmIts best to stick with as high a gear as possible because to higher gears are thicker and will hold up to the torque your 5.0 puts out better. I would not recommend going lower than 4.56's. If you do decide to re-gear, look into buying a cryo-treated set or getting them treated for that extra strength...
http://www.longfieldsuperaxles.com/
