A lot of the Saginaw boxes SHOULD have the same mount up...so if you wanted to go to the trouble of running a Ch*vy Truck 4x4 box...and then later change to a 2wd box for crossover steering you should be ok...just measure first!!!

 

go to discountsteering.com They sell a complete kit to install a ford 2 wd box. If you look at what they sell you will see very easy to manufacture . I have installed a few of the 78/79 boxes and you do have to notch frame, box it, and be exact on drilling holes so pitman arm doesn't contact bottom of frame. What I have read about the 2 wd box is that it works good as long as tire size isn't bigger than 37/38. the box must be a little weaker. I have been thinking of this kit on my 74 highboy with 65 body and no bigger than 35" tires.

 

I designed one for Highboys...That Doesn't require Frame Mods or drilling...just a cut on the core support...uses 2wd box...77 1/2 to 79 pitman...direct bolt in using original gear boxes holes....either shorten steering shaft or find F100/F150 with manual steering and the shaft works ok...because it is shorter. 2wd power steering lines work....Uses Tie rod ends from a 1969 F-250 4x4 and a Custom made sleeve (DOM that has been threaded and has the clamps)

 

Thanks ND, that is a very good thing to know!

 

All 1967/75 F250 4WD's (High Boys) use the same manual gearbox:

C7TZ3504A / Gearbox housing casting number: 35JC10
-------------------------------------------------------
1976/77 High Boys use a different manual gearbox:

D6TZ3504C / FoMoCo ID tag code number: D6TA-HA / Housing casting number: 378AS022

 

If using the 2wd ford box, some mods still have to be performed. Clearing the sector shafts often requires a frame modification. This makes the 2wd box less than desireable. That sector shaft is pretty long and is very prone to breakage.
If you plan on using this box, the easier install would be a 4wd box (3 bolt) used in broncos (fullsize) or F150's. Again, this mounts to the outside of the frame, and it too can be used as a push / pull style, or the better crossover design.

Here is a 3 bolt box in my other truck:

 

I converted using the 78/79 F250 4x4 method and it works fine, but I think If I would do it all over, I probably would have used 75F350's method. The only thing is though, I wanted to leave my truck a stock height with the stock leaf springs. It doesn't look like the pitman arm would clear the springs.

 

The previous owner of my truck installed a 2wd Ford ps box, mouned straight up and down, with a 78/79 pitman arm(I think). The draglink was cobbled together from parts I do not know of, but it is adjustable, and looks factory.
Regardless of which mod you go with, I suggest making it a bolt in deal, and little or no welding to the frame-some inspection places can and or may not allow any welds on the frame.
Do some research and build it right the first time!
yes I need a digital camera, heh

 

Ok 75F350 you have both the saginaw and 3 bolt 4x4 box. Which is better? Both can be used for push/pull and crossover right?
Is there any benefit over the factory set up if left as push/pull?

I think I could find the saginaw easier. Is one easier to install then the other?

 

Interesting that you mention this. There are many factors here, and overall clearance is the main factor. I have another truck that has been highly modified ('the getter') and it uses the 78/9 box. Well I run a large aluminum crossflow radiator, and this box takes up quite a bit of space. The advantage goes to the boxes that mount outside of the frame.
Heak, I even remember that the saginaw box uses one stok hole in the frame. This made it easy to align and drill the rest of the bolts. Now, the saginaw box will have three bolts that line up with the frame and one that is below the frame line. I added a large chunk of steel that was one inch thick to provide support for the very bottom. I tried to use only three and busted the tabs off of the first box. I needed to mount the box this way because I needed the extra angle to create as much clearance as possible for the pitman arm and spring during full compression (driver side). This truck flexes a bunch. AFter I busted it, I repaired it. Lesson learned there. Been turning 40 inch tires for a few years now, and zero problems with this box. This is a 4 turn 16:1 box actually donated from an old dodge motorhome. Stock pitman arm too.

Alright, now the 3 bolt, ford box. This box is much easier to install, since it has only three bolts and was designed to be used in a ford anyway. It can be used in a push pull configuration however, if super large tires are used, the pitman arm can strike the tire at full lock to lock turns. Spring clearance and tire clearance can be an issue when using this method. Lifted trucks should use crossover, and there should be no debate there.

Now the reason why x-over is so desireable, is because of the amount of movement the axle actually makes during suspension cycles.
Alright lets break this down;
On a leaf spring suspension, the axle moves towards the shackle during compression, and moves away from the shackle during suspension extension. Yes the wheelbase does change. Now if the steering box is connected to the axle with a short drag link and this drag link faces foward it cant move along the same arch, or make the same changes as the suspension cycles. Since the steering box is stationary, the only thing that can happen is that the differences in lengths turn into "bumpsteer". The drag link is forcedon direction or another and the end result is feedback of the steering wheel. Now this can be worse if the truck has enough suspension travel. At full driverside extension, the steering wheel has to turn all the way just to keep the wheels straight. This limits the turning radius to almost nothing.
Now the fix is to permit the axle to move without binding it up with a steering linkage. well some sort of linkage must be installed, so installing it to the pass side knuckle eliminates the above mentioned problems. See, now the drag link can move foward and back along with the axle as the drag link runs parallel to the axle, and will move right with the axle during any syspension cycles. Bumpsteer will not be transfered back to the steering box since the axle does not move from side to side. (not suppoed to anyway) so the axle is not working against the drag link.
No when the axle articulates, the drag link remains parallel to the axle, and the turning radius remains the same. No issues here, and the truck performs extremely well on and off of the road.

All of my trucks are really a pleasure to drive, but the red truck rides like a car. Steers like a car and one almost forgets that they are driving a truck so large. I dont have any troubles running 70 to 75 plus and letting go of the sterring wheel.
The girlfirend weighs a little over 100 lbs, and drives this thing to the grocery store. It turns that easy. No more fighting the wheel, and struggling to turn the truck. This has been a modification that is well worth any time and money spent.

I have broken the sector shaft on the 3 bolt ford box, and these are not that cheap. The saginaw has been fine as long as it stays tight. With either box, routine checks of the bolts should keep things under control.

 

Make damn SURE the steering gear bolts that retain the gearbox to the frame are tight.

Ford had a major problem with these trucks.

When the bolts work loose, the gearbox wiggles around.

Sooner or later, the frame CRACKS.

I kid you not!

2WD, 4WD...M/S or P/S...it makes no difference, this problem affected them all.

There was no Ford fix, no recall. Ford later came out with longer grade 8 bolts.

Dealers welded up the frame, then welded on "homemade" re-inforcement plates.

 

Would the location for the push/pull and X-over on the 3 bolt outside of the frame mounted 4x4 F150 mount be the same?

And what pitman arm would you use for the push/pull and the X-over?

(I am still up in the air as to how I am going with this conversion. But I want to start with push/pull then later go with X-over.)

 

I thought I had steering issues as you are describing, then I really took a closer look on my 76 F-100, the steering (rag joint) was shot. I replaced it and more than half of my steering play was gone. I can live the rest of it!

 

Loctite is VERY Helpful in these situations as well...super strength stuff that takes an impact gun to remove!

 

You have to be very careful with the rotation of the box you use. IN some cases, you cant use one of the boxes mentioned, as these boxes turn the wrong direction if used as a push pull. Steering input will be backwards.