I was being ironical.. lol
Don't worry about the motor blowing up. It's not revving dangerously fast at that speed unless you do, in fact, have 4.10s.
You should also take into considersation, and I wish some people I know IRL would listen to me too, but;
Lower RPMS does NOT always mean it's getting better mileage. If the motor's dogging at all, or doesn't quite have the torque to turn that much gear, it's actually going to get worse.
But my recommendation still stands... If you find a good deal on a 4wd one, I'd say go for it. Even if you don't need the 4wd, the 2LO is still there, and if you do ever change your mind, it's there. Or if you ever sell it, you can bump the price up because the swap is half done already.
lol sorry at a quick glance i though you said you had a good ax5... shoulda read more carefully... anyway i think that's probably what i'll have to end up doing, i was just trying to avoid all of that extra hassle and parts hunting....