Thanks again for all the responses. I'm beginning to get a game plan together.
As much as I'd like to do a diesel conversion (and will someday), I don't have time for it now and it would not be cost effective - I'd pay more for the conversion than I would save in gas costs.
If you guys really think I can get 15 mpg out of my Cruiser I would be ecstatic. That would be huge, literally a 50% savings in gas vs. the 10 mpg I was dreading. I think I'll keep the engine mods minimal for now and stick to a good tune up and get rid of the catalytic converter. I'll probably also put new headers on, as much for the experience as the efficiency boost. Truth be told I don't know squat about engines, though I intend on learning as much a I can before I go. Same with Spanish. I need to learn how to say "Here is all my money, please don't kill me."
I might do some other engine mods, as long as I am not introducing additional points of failure or reducing the reliability of the 2F in doing so. Maybe a DUI distributer as Tapage suggested. Sounds like I need to talk with Jim C. about about Carb rebuid too.
To answer some of the questions I've gotten on this thread:
I do have a large aftermarket gas tank - I think it's 42 or 46 gallons. If I can get close to 15 mpg that would translate into a huge range. That reminds me, I had to replace my fuel sender and had a very hard time finding one that provided the right resistance that would fit my tank. I found these guys who offer a variable resistance fuel gauge sender cut to size that seems to be doing the trick:
www.centroidproducts.com
My engine seems to be in pretty good shape. It's got 163K miles on it, hasn't been rebuilt yet. I haven't done a compression test yet so I don't know about that. It burns about a quart of oil every fill up, but given the size of the gas tank fill ups aren't very often.
I've got 30" tires, haven't changed the diff.
Thanks for all the links to others who have done similar trips. The websites are awesome. I recommend anyone who hasn't seen the sites check them out, if not for the cool pics of S. American people and countryside then for the beautiful photos of Land Cruisers in all their glory in their natural habitat. It's like seeing eagles soar, or happy dogs run; the world seems as it should be when you see a beautiful fj60 covered in mud with lush moutains in the backdrop.
Thanks again for all the advice, and please keep it coming. If you guys are interested, I will post some photos of the truck when she is ready to go and will share any exciting stories from the trip.
Mark
edit 04/06/06- The Centroid sender did not work out afterall so I can't recommend it.