I am going to lift it, but have a million ?z for all who have lifts.

[Brewski*]

Yes, I am going to lift the Red Rocket. But I have a million questions about what to do and how to do it. I think I need 4" lift minimum to clear 35" tires. Correct? What about rear springs: Do they make a great difference or just cost more money? My 3/4 ton is pretty stiff back there already. I know the blocks look crappy but who is really going to look besides me?
The Rocky Mountain suspension page Rocky Mountain says this:

To correctly lift a solid axle General Motors vehicle, it is important to achieve the correct drag link angle. Most vehicles can be lifted 2" and maintain the correct angle. Lifts over 2" increase the distance between the link’s two attaching points causing the vehicle to "wander". These adverse angles also can cause premature wear on other steering components shortening their life expectancy. There are several options for correcting this angle, however, they all require an open knuckle, 3-bolt steering box. Prior to 1973, most vehicles are not so equipped. The best option is to upgrade the steering box to a 1973 style open knuckle type in order for the various dropped steering components to fit. No steering correction is made for the earlier version steering box. Once updated, the options for steering correction include steering arm, pitman arm, adjustable drag link or steering blocks.

IS ALL THIS NECESSARY? Has anyone here ever done this steering box change out? I don't want my truck to wander or tear up the stearing parts. What have you all done to your trucks to make them ride right? Any help much appreciated~!

[SWEET7T]

They are right, with the steering being at a greater angle; as the suspension cycles up and down, it will cause your truck to drive left and right (same idea as the trailing arm 2wd trucks). I don't know what is available for these trucks as in lifts, but I have always seen 'drop pitman arms' installed. Are they not available for these model trucks?

You "could" always go without it, but from my experience with an old CJ of mine, before I took care of the steering angle, you could see the tires turn left/right with larger bumps and whoops!!!

Hopefully, somebody can tell you more about the steering box swap...

[1969 GMC]

i am confused about the steering box...i don't think you have to swap boxes to lift, you just need the dropped arm. i know that you do need to swap steering boxes if you are converting to crossover (or hi steer) steering, because you can clock the pitman arm to differerent angles on a 2wd steering box, and you cannot on a 4wd steering box. you probably do not need crossover steering for a 4" lift, at least from what i have seen on this board. you will just need the lift kit and the dropped steering arm. bumpsteer will be a bit more noticeable, but just pay attention when driving i guess.

what are you going to do with the truck? actually offroad it or just want a better stance for street driving?

[Brewski*]

The wheels and tires are the ones off the H2 Hummers the size is:
Wheels: 17x8.5Jx18.0
Tires: BR Goodrich, All Terrain, KO, 315/70R/17, 34" tall, 10" tread width 12" wide at widest point. I was told the 2.5 inch lift would work for 34" tires with no steering box replacement needed. Anyone know for sure? I would much rather do the 4" lift just to be safe and allow more travel.

[JIMs70GMC]

I believe they make some generilations and assume prior to 73 had the 68 style gear box. 70 and up have the same style gear box and in late 70 they changed to metric fittings. I have 2" drop pitman arm on my truck with about 3" of lift. The pitman arm fits 70 and up trucks. I skipped 69 because i'm not sure which type gear box they had. You should be find with your gear box. If you go with 4" use a raised steering arm (cheaper).

[Mike C]

Whoever wrote that passage you quoted was not very educated about GM 4x4. The steering box is pretty much the same from 68 up, but the front axle is different. In 1970 they switched to the open knuckle front axle (some 69 may have as well). This means that you can see the u-joints in the front drive axles just inside the wheel. You will need 4" lift to clear 35's. Do the steering arm. Do the rear springs. Even though yours is pretty stiff, it will have settled in 30 years. Also, the blocks increase the load on the springs themselves accelerating their decline. I bent the axle housing perches on my Jimmy using blocks. This required extra work and extra money at a later date. Just buy a 4" kit that comes with rear springs and the steering arm. If I was spec'ing my own kit, I would do softride springs in the front, HD springs in the rear with the Velvet-Ride rear shackles. The 2 1/2" springs on the 4x4 should be able to use the 73 and up Velvets. If you do wind up needing a steering box upgrade (mine was completely worn out after 350k miles) get the variable ratio box for a better on-road feel to the steering.

[smokekiki]

I have a 4"tuff country lift on my truck.Front and rear springs.It rides better than stock did.With the dropped pitman arm it is no problem.I had to change front brake lines.The stock were a little to tight.Not a bad idea if they are old anyhow.In Pa we can't run blocks bigger than 2".

[Dean]

Blocks in the back would definitely be cheaper. I use the Skyjacker Softride 4" with new springs all the way around.

You will also need the steering arm, longer brake hoses & I would replace the bushings on the upper rear front spring shackle to the frame. I have the part numbers I use for the brake hoses if needed.

You can still get a new steering box from GM for an 85 K20 that is the same except for metric fittings on the hoses. I converted my blue 72 K20 to this. I did have to cut two small holes in the inner fender for the hoses. I purchased a rebuilt gearbox for the green 71 K20 that I am currently working on from Pep Boys. The gearboxes are expensive either way you go, but what a difference they made on my trucks.

I don't recommend the Nitro shocks either. I'm now using the Hydro shocks and I like them a lot better.

And don't over tighten the new spring bolts. Double nut them if you are concerned. I had my very first one over tightened and then read about it in a 4x4 magazine. I loosened them and double nutted them. What a difference that made.

[1972chevy4x4]

I installed a 4" inch tuff country lift that came with both front and rear springs and a correct steering arm for the changed height. It works great. I have a buddy that has the rear blocks and you can really tell the difference in ride comfort. I have 33 on mine and have plenty of clearance.