Webbers are a great swap, as is a Side-Draft conversion over to a set of Harley carbs. I'll let other people chime in on the best carb out of the two.
To run 31" tires transfer case gears or a lower differential gears will get you most of your power back. I'm a big fan of putting new gears in the t-case and leaving the front and rear end alone. A set of 4.8 or 5.8 t-case gears should be just about perfect.
For the lift if you have access to a welder then a SPOA, or Spring Over Axle, lift is the quickest and easiest way to fit 31" tires, but there are a couple ways of doing it. Just depends on how much fabrication work you can do and how much you want to spend.
For a nice adventure rig some 2.5" OME Springs and 30" tires with a 4:1 transfer case is a great way to go. Small enough you won't break stuff but big enough to go most anywhere, especially with lockers front and rear.