So... I went ahead and did the deal. I was able to get the thing rolling and drive it home. I had friends follow me just in case.
The only thing I really cared about was the frame. The frame was STRAIGHT and was impressively rust free. The body was a little beaten, but wait till I get through with it!
Here's a picture of what I had when it got to my driveway:
This is already after the first modification.
There had been a horrifying hard top on it. The meth-head that owned it previous to the guy I bought it from, decided that it would be cool to try to make it into a hard top bikini style... almost like the FJ45 pickup truck. He chopped the hard top in the middle and glued the ends back together with a strip of fiberglass. I tossed that thing immediately. It was worthless.
Then I got underneath and took a serious look at the engine.
Major parts were missing.
No cover on the bottom of the bellhousing.
The e-brake cable was dangling.
There appeared to be less than the total number of connections intended to end at the transfer case.
An MGD beer cap sealed the clutch master cylinder.
JB Weld closed off the end of some piece of tubing I couldn't even identify.
The transmission was not the original 3 speed on the column... it had been replaced with a 3-on-the-floor which had necessitated a cut-through in the tranny hump.
My first goal was already going out the window.
I had thought it would be kinda fun to base the project off of near original parts... put a crawl box in between the existing transmission and transfer case... use the F engine...
I started talking to Sean (Sean K. - who recently decided no longer to participate in forum chatter... it's ok, I still call him at work at least twice a day with ideas or questions...)
Sean suggested several things.
First off, the transfer case is weak. If I wanted to stay with that FJ40 configuration, I should upgrade to the Orion which is a stronger iron case that won't break in half under crawl conditions.
Next, the axles would be maxed by crawler sized tires... also strongly consider upgrades.
Things rapidly mushroomed from there.
The FJ40 has an oddball arrangement of parts relative to many things we see nowadays. In most 4x4 vehicles we see now, the engine crankshaft is in the middle of the vehicle, followed by a transmission, in the middle of the vehicle, followed by a transfer case also in the middle of the vehicle. The transfer case splits the output from the powerplant into a rear drive shaft and a front driveshaft. The rear driveshaft continues down the midline of the vehicle. The front driveshaft is either on the right or the left side of center. The rear differential housing is on center. The front differential housing is off center.
In the FJC, you can't really see that so much because the clamshell housing for the differential is hidden up on top of a crossmember and behind some skid plates, but it's there, on the left side (driver's side). On any solid axle setup, it's readily apparent.
The original FJ40 plan was completely different.
Instead of having a midline driveshaft to the rear axle, the transfer case offsets BOTH the front and rear driveshafts to the passenger's side. Both of the differential housings are offset.
This meant that if I were to retain the original transfer case or a stronger clone, I'd be forced to use either FJ40 axles or some other type of axle that also had offset front AND rear differentials... perhaps from a larger Land Cruiser like an FJ80.
At the same time, I was looking at the engine and transmission issues.
I wanted a GREAT crawl ratio. This meant a dual case crawl box as far as I knew, but inside a vehicle with a stock 90 inch wheelbase, that could be a problem! There could literally be not enough room to bolt these parts together.
That's ok. Everyone seems to agree that 90" is WAY too short a wheelbase for AZ rock crawling. I only improve things if I start to splay apart the axles... so I shouldn't let that stop me from putting together the transmission system that I dream of.
...but what to drive it??
The problem with the original F series engine - although it is a marvel of longevity (this one should have been dead long ago), is that it's a carburated engine. This poses two problems for a crawler, according to my homework.
First off, carburated engines idle with low fuel and low air intake, and then increrase both proportionally with throttle opening. They have very low power at low throttle, and high power at high throttle. A crawler needs to have good power even at low RPM.
Secondly, a problem with carburated engines is that they were naively designed to run UPRIGHT and they don't necessarily fare very well when tipped on their sides or steeply stood on end. This can be a problem when the plan is for the engine to be put in some pretty awkward positions and the absolutely COUNT on its performance, once there.
The solution to both these problems is fuel injection. Fuel injected engines perform better at low speed, AND they do better in off-camber positions.
The problem is that I don't know THING ONE about working on engines, let alone fuel injected ones.
I found it only mildly reassuring that many people swap fuel injected Chevy engines into FJ40's, however, the party line is that it's do-able even if you don't know how to deal with the fine points of fuel injection, because the little computer thingie does most of that for you... as long as you wire it in correctly.
So... since I decided to go with ginormous tires, I decided to upgrade to 1-ton axles which are compatible with a standard centered rear driveshaft design and an offset front axle. I was then able to use more readily available parts like the Atlas transfer case which packs more gear reduction into less distance, anyhow... improving the control I have on the length of the powertrain from engine to driveshaft.