79 f350 crossover pittman arm???
 

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I was about to typ out all of the variables that would otherwise be overlooked, but fortunately you are the originating poster.
You have covered all of the bases, and should have this under control.

For 1 ton tre's you will have to re taper any hole that the GM tre is going to fit. This includes the steering arm.
That being said, I would measure the pitman arm that you have. I believe that this arm is the same for 4" kits as it is for 6" kits, the 6" kits simply use a different drag link, (more drop).
Ok, so to answer your question, you may look into just re-indexing the arm and cycling the suspension. Remove the drag link from the pitman arm completely, and compress the driver side suspension. Once full compressed, turn the steering wheel (remeber the pitman arm now swings from left to right etc). YOu should get a good idea on whether or not your spring pack will clear under full compression or not. Pay attention to the size of the tre and if you have enough clearance, then go for it. Use it.
Perhaps take it a step further and make up a mock drag link and see if you have the clearance under the crossmember to clear that too. If you can raise the drag link, then you can modify your current pitman arm.
Since these are forged, they can take some heat so you can heat it up and flatten it out. Yes it will get longer, but not so long that it will have any ill affects, as long as you dont flatten it out straight or something out of reason.
Some angle can be changed with a raised steering arm too, but for this amount of lift the flat arm should be alright.

Have any ideas of which steering arm you plan to use? I assume the Es2026, and 2027 tre's will be used?

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Small minor and major differences in the tapered hole. I have found it much easier to find a 2026 or 2027 in odd places where 4wd parts are not common.
Since the 2026/7 are drag link ends they are pretty easy to find and offer a longer threaded section. This helps some with additional adjustability or minor corrections if one has to be modified.
2233L, 2234R, 2026R and 2227L are all the ends for an '85 Blazer, if you need an application.

As mentioned the 2026R and 2027L are the drag link ends on the blazer. They use the "large GM taper" and have a higher angle capability. (debatable)

The 2233L and 2234R are the TR ends and use the smaller or standard GM taper. The 2233L is the long one and has the extra hole in it for a steering stabilizer. This is the TRE and hole frequently re-reamed for use in "inverted-T" crossover steering setups.


What good is cool info without a pic right?


http://i292.photobucket.com/albums/m...chebbyTREs.jpg

The 2010L is just a good match for a 2234R if you don't want or need to use the extra long 2233L.

*Note this is important information right here. Yup genuine "gold" in one reply*
Everyone asking for this information can get it right up there.

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Thank you, thats nice of you.

I have many things to "think" about the many aftermarket arms out there, and while some are desirable, some are not. I can't (won't actually) talk bad about any specific manufacturers, but I can suggest some things to look out for.

Machined surfaces between the arm and the knuckle are very important for strength. The arms that you mentioned cant allow the arm to sit right on the knuckle so all of the clamping force is applied to the cap, and not directly on the knuckle. Notice high end arms are not painted nor are they coated? Clamping force.....thats important. Its important because the friction between the steering arm and the knuckle is what provides enough support to keep the studs from doing all of the work, and this prevents broken knuckles.
Next, the types of fasteners used is also just as important. Some I have seen use bolts, and some studs. Obviously studs are superior, and can provide a more rigid method of support here.
Once again machined holes are critical. Higher end arms have a very tight tolerance here, and stay tight against the fastener.
Method of applying the load or twist to the fastener. Well, the SAE bolt itself is just not as perfect as one would think and is not suitable (the tolerance anyway) to secure the arm correctly. So what do we do? Do we find some aircraft fasteners? Well,,,,yes, this is an option, but not many have this option, so the next thing to do is to look at GM for yet another engenieering marvel The split cone (conical) washer. Yup, our buddies over at GM have the answer. This is an SAE stud with a split ring cone that is designed to take up the space and make up for the tolerance problem. Yes, machining the hole is still critical, but the use of the SAE stud is now acceptable because of this fancy little cone washer.
Part #3965138 available from GM. Most steering arm manufacturers will also stock these will include them as part of the kit when you pruchase.
The arm will have to have a taperd hole to accept these but during the machining process, this is simple. I tell you what, these things stay tight and keep a tolerance, thats for sure.
Last bit is to simply use a "Stover" nut on top, and these aircraft style nuts ensure proper torque through many loads.

I have some pics of these items, but cant find them. I have hundreds of images and sometimes finding them is tough.
Ever take a Toyota knuckle apart? They use this design. Its a good one.

Lets see if this actually answers your above question about the differences in the trs that i mentioned and the ones you intend to use:

http://i292.photobucket.com/albums/m...ifferences.jpg

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They are all the same size thread size. There are several guys that speculate the strength of one over the other. Some like the shorter versions while others like the longer ones with the larger area around the end. I have seen little difference in overal strength, and I have had to bend the 2026/7's in a press to change the angle. This improved suspension cycles, and help to keep the ball inside of the joint.

Here is a shot of a new set up for you. Should hit the streets real soon.

http://i292.photobucket.com/albums/m...ongnicely2.jpg

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You are awesome! Yes this is a 2wd truck,,,,errrr was a 2wd truck. I had planned on doing a coilover conversion with this but I could not "steer" (see the pun there?) away from the leaf spring.
So many folks were asking about the 2wd to 4wd conversion, I decided to do one and set an example of how I do it. Not necessarilly the right way or a perfect way, but the way I have been doing them, you know what I mean?
This is a mock up, and in the mock up stage so that I could fit everything so not all of it is as correct as it will be in the finished product. I will have pics and a build thread on this rig when it is complete. I like to create the thread all at once so it can be viewed all at the same time instead of being dragged out for months.
I have run the steering linkages with both threaded inserts as well as just threading the tube. Both are alright as long as the tube is sized adequately.

A steering arm like this can be purchased from several companies but this one was machined locally. Kind of stole the look from some others that were seen and used.
Could have gone a little more on the heigth, but it works well enough for now. Gotta see what the springs are gonna do as they settle.

Man, is that axle SEXY!!!! Did Steve tell you I may have a complete 79 F-350 truck minus bed lined up with 60's front and rear for 500 bucks?? Axles for my Crew Cab!!!

I want 2 of those spring plates !!
Very nice as usual Ed.

Yeah, thats been around the rumor mill. Thats awesome!

Thank you. I might add that the big hump in the middle will act as a bump stop surface and the pass side is three sided with a hole through the middle. It can also act as a mount for a trac bar if required. They have come a long way since they first ones, and they bring the beef if you know what I mean. They are heavy duty!
Rears are nice too:

http://i292.photobucket.com/albums/m...nwith14Bff.jpg