Okay.... some good news.... some bad news.

1st the bad news: Turns out be it 2wd or 4wd the same housing is used. Only difference is the installation of CV shafts feeding into the lockouts.

In saying that the hub diameter needs to be 4.5". This leaves you with 2 choices to fit the Ford wheels that I choose. (turn the hub or cut the rim.)

I reviewed the rim in comparison to the steel rim clearance spec from center hole oppening to lug hole opening and determined there to be more than adequate material to be able to safely cut the center hole diameter larger.
This allows me to be able to at a later date install 4wd if I find a reasonable priced donor vehicle.

I took the front 2 rims and the spare and cut the center hole diameter out on a Bridgeport Mill. By doing this it allows the rim to seat properly and retains the OEM specs between the hub center and the rim so that the rim can't shift once tightened down with the lug nuts. It gives a nice finished look and most important it is perfectly round. I used the stock lug nuts back and there was plenty of run down on them.

Only visable drawback is the caliper clearance is close to the rims backside. For me this isn't an issue since at this time the vehicle won't see much off road usage. At some point when I convert this over to a 4wd  I will entertain boring out the lug holes out and using a steped lug nut with a lock washer so that I could manufactuer a .25 shim spacer to slightly offset the rim to allow more caliper clearance.

Now the good news... 235 x 75 15 fit under the stock truck with no modifications for road use. I drove about 10 miles on it today with no issuses. But, I am still going to put the 4 door springs and Jeff's 2 inch strut and spacer kit under it as soon as the new gas charged struts and Cavaliar gas charged shocks arrive. I want it to sit a little higher and be able to reinstall my mud guards. (see next sentence...)

I did have to remove my front mudguards because the tires did want to bite them when I turned he wheels to the extreme inside in either direction. It drove straight and true enough you could release the steering wheel and it would track right on down the roard as a lil' Tracker should do... ;-)

Only thing for now is figuring out a good air pressure for a more comfortable ride. I am running Big O AT's and the tread design is fairly aggressive plus the manufacturer recomended cold air pressure is 50 lbs. WOW. I have them backed down to 40 right now and that seems to be a little better.



    

.......... the manufacturer recomended cold air pressure is 50 lbs. WOW. I have them backed down to 40 right now and that seems to be a little better.    

That bit I don't understand.  Is that recommendation for a specific vehicle (yours) or is it the maximum pressure for that tyre?  I would have expected the right pressure to be little different to that recommended for the vehicle with the stock tyre, as tyre pressures are much more dependent on the vehicle than the tyre.

That is the recomended cold air pressure as printed on the siidewall of the tire. In driving the vehicle it just felt much too hard. I then reduces the pressure to 40 lbs. and it feels a little better. I am going to call the NTB store today and ask the what they recomend.

Most likely for my style driving I will keep my eyes open for a set of HT (highway tread) style tires and swap or sell off the agressive XT (extreme tread) tires. 

Tire pressure, do not go by the sidewall markings. That is the maximum pressure recc for that particular tire. The recc pressure for tires on your vehicle is on a sticker in the door jamb. My ZR2 sz 26 lbs and I run 28.
On tire sizing, 1010 Tires, http://www.1010tires.com, has a tire size calculator rhat gives and compares approx sizing.
Tire Rack,  http://www.tirerack.com, has lots of good info too.
I have the 15x6 rims and have compared tire sizes, also considering the GV 16X7 rims , so many choices
 On our `97 4dr I have lowered it about 2" with 15X7 rims & 225/75 tires. no problems.

Sorry its taken me a few days to get back to this. Kinda in the middle of getting my winch mounted and wired up right now.

But, Here is the deal.... normally I would agree with utilizing the info on the door jam providing that you are riding on a comparible tire suggested by the manufactuer.

However if you are driving on something modified that is completely different you have to utilize a mix of the tire manufactuter and the vehicle's suggested specs.

For example I owned a CJ7 with 14x38 Ground Hawgs and they were in no way comparable to the 215x75 Firestones that were originally on it.

When a vehicle as light as ours is lifted with much larger than OEM spec tire the vehicle OEM specs are modified as well. In saying that I called the local Big O tire dealer (now NTB Tire). They calculated the vehicle's weight and the tire size change. From the change made they suggested the air pressure be somewhere close to 35PSI.

Since my original post I have ran the tire shops suggested PSI and it feels about right. In making the suggested change the ride has improved and most of the "Howl" of the tires down the road has subsided.

Hope some of this makes some sense... in most cases its as simple as making a phone call like I did. Or, you can try trial and AIR (ha-ha pun intended).