Odd leveling '97 Z71 Silverado 6.5TD

[Nylanderz]

Hello everyone! I've been doing some height measurements on my truck and,well let's say i'm a bit confused..
The previous owner has installed 1,6" lift blocks in the rear (guess that's the most you can lift it without changing to a longer pair of u-bolts) and the front is all stock.
I was thinking if i could level my entire vehicle out without alternating to much,though the rear will be a problem, guessing the leafs/suspension in the back are in poor condition since it's higher on the right side then the left..
I've made a,what i think is a fairly good picture showing the measure's i got.

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Could anyone help me how to level this out? Atleast the front part, i do believe i will have to live with the rear heights not being correct or i'll have to replace my entire back suspension with new parts.. I would like to gain a couple inches in the front too, to fit some 285/75's.
I know about torsion cranking, but is there anything else that could cause these measures to be off, i mean my truck is like the leaning tower of pisa right now.

 

[Nylanderz]

A thought occured to me, is it possible my height differences could be so much off due to uneven bad cab/bed mount bushings?

 

[df2x4]

The rear being higher on the passenger side is a common problem with these trucks, both of mine are the same way. The reasoning that I've heard most is that the fuel tank is placed slightly towards the driver's side of the vehicle, and the extra weight of this plus a driver can cause the driver's side leaf spring to wear out a little faster. Not really sure of a way to fix this except getting a new set of leaf springs or finding a place that will re-arch yours. Cab and bed mounts could be part of the issue, however I'm willing to bet that your leaf springs are the cause. The rear of these trucks sits about 2" higher than the front from the factory. Considering you have lift blocks in the rear and your height difference front to rear is still only approximately 2", I'd guess that your leaf springs are sagging very badly. If I were you, I'd think about getting new leaf springs and ditching the lift blocks and see where that gets you. You should be able to adjust your front height slightly via the torsion bars/keys. After sorting this out, if you would like to lower the rear end a little to level it out there are plenty of places that sell 2" drop shackles for the leaf springs.

EDIT - As a side note, you should be able to run 285/75s at stock height no problem. I ran them on my Suburban for quite a while with no modifications or adjustments, no rubbing.

 

[Nylanderz]

The rear being higher on the passenger side is a common problem with these trucks, both of mine are the same way. The reasoning that I've heard most is that the fuel tank is placed slightly towards the driver's side of the vehicle, and the extra weight of this plus a driver can cause the driver's side leaf spring to wear out a little faster. Not really sure of a way to fix this except getting a new set of leaf springs or finding a place that will re-arch yours. Cab and bed mounts could be part of the issue, however I'm willing to bet that your leaf springs are the cause. The rear of these trucks sits about 2" higher than the front from the factory. Considering you have lift blocks in the rear and your height difference front to rear is still only approximately 2", I'd guess that your leaf springs are sagging very badly. If I were you, I'd think about getting new leaf springs and ditching the lift blocks and see where that gets you. You should be able to adjust your front height slightly via the torsion bars/keys. After sorting this out, if you would like to lower the rear end a little to level it out there are plenty of places that sell 2" drop shackles for the leaf springs.

EDIT - As a side note, you should be able to run 285/75s at stock height no problem. I ran them on my Suburban for quite a while with no modifications or adjustments, no rubbing.

Hmm allright, that i didn't think off! Well i guess after 200k miles with the original leafs that could cause the suspension sagging very badly. I'll consider replacing the leafs instead of the cab mount bushings.

Alright then, i should be pretty clear running 285/75's, cranking the torsions should gain me a little height too.
But how much would you be able to crank the torsion's without killing the IFS,shafts and what not?

 

[df2x4]

But how much would you be able to crank the torsion's without killing the IFS,shafts and what not?

That I'm not sure about personally as I've never adjusted mine, sorry! Thinking about it now, your leaf springs might not actually be as bad as I thought. If the previous owner installed lift blocks in the rear then it's entirely possible that he cranked the keys up in the front 2" or so to match. If you post pictures of your angles on the front end I'm sure someone who knows more than me can tell you what's going on. You might already be cranked!

I seem to recall seeing a thread on here where someone cranked their front end up 3" on stock keys and stating that it rode horrible and wore parts out in less than a year's time, so I think that's about the highest you'd ever want to go.

 

[Nylanderz]

That I'm not sure about personally as I've never adjusted mine, sorry! Thinking about it now, your leaf springs might not actually be as bad as I thought. If the previous owner installed lift blocks in the rear then it's entirely possible that he cranked the keys up in the front 2" or so to match. If you post pictures of your angles on the front end I'm sure someone who knows more than me can tell you what's going on. You might already be cranked!

I seem to recall seeing a thread on here where someone cranked their front end up 3" on stock keys and stating that it rode horrible and wore parts out in less than a year's time, so I think that's about the highest you'd ever want to go.

I suspect any cranking is bad cranking.. Anyone that mind explaining how the geometric's and angles change when cranking the torsions? Or an illustrative picture showing how it works and alternates when cranking the t-bars.

Hmm i'll look into that, aren't there any other way to know that any of the previous owners have cranked?

Oh no i will not be cranking them 3", that would as you say be killing my suspension and what not.. I would like to gain at tops 1,5-2" to help even it out bit.