How does adding a leaf to the existing pack work? I know you add it and it lifts it, but my question is how do you know which leaf to add to a stock sami leaf pack? Can you just use one that fits or are there certain criteria? I've heard mention of using S10 springs and getting 1-2". Can someone enlighten me? I can get my hands on all kinds of S10 parts where I live. Also, can I get some more detail on how to actually go about adding one to mine? Thanks for replies.

spring steel is spring steel, just find one that has the same width and cut and shape the spring to fit where you want it to go.

So i could just find one that is the same width as mine, cut it to like 8 inches long and run it as the shortest of the springs in the pack and that alone will lift it 1-2"? That sounds too good to be true.

NO...
The idea is to not only add a leaf , but to add arch at the same time.
We usually cut the new spring to fit in the pack directly below the main spring.
This makes it the second longest in the pack...
Lift is determined by , how much arch the new spring has , and how stiff the new spring is....
And of course, the thickness of the new spring...
 2" is asking a bunch from this mod......Boxcar...

Sammies ride stiff anyway. Add a spring and you get stiffer. If you just want a little lift, there are easier and better ways to do it. Rear up front, Shackle reverse, OME springs or even longer shackles. Add a leaf is good if you are carrying a real heavy load but ride like a brick empty.

I don't want 2" just 1-1.5"... what are some  vehicles to look at taking the springs from?

Im already doing the 1.5" shackle lift

He's right .There are easier ways to lift 1.5"..
 Lets start with your current set up.
Is your Zuke totally stock SPOA'd  ? Tire size ? etc.
Do you intend to wheel it , or is it a DD ?
...Boxcar...
 

It's pretty much bone stock (ugly rims) and it's a DD for now. I've got shackles on the way and they should be here by this weekend. I don't want ridiculous lift just like 3" and I'm on a budget so I'm trying to find a way to get the other inch without going broke. I do have a few trails around me that I plan to ride and I've riden them before but I don't need a rock crawler to make it. Tell me how this shackle reversal works and the RUF

 Repack the springs. Using a cut down main spring from a donor rig....  Or pick up another set of stock rears .
Running rears all the way around will add 1 - 1.5"
But will require other mods to work correctly.  Due to the axle relocation they will cause.
 Don't go over 1.5" with the shackles......Boxcar...

The shackles are 1.5". So what's shackle reversal and how's it work?

A shackle reverse system is a bolt on or weld on system that reverses the spring mounting system on the front axle. (shackles in rear / spring mount in front.)
 Most Kit's start at $250 - $260
A very good upgrade to your Zuke.. It will drive like a dream.. And add stability....Boxcar...

S10 leafs are 2.5" wide.  Samurai leafs are 2" wide.  YJ leafs are 2.5" wide.
I am using the second longest leaf from an S10/blazer pack with my 4 leaf YJ packs.  I got 2" of lift out of it and didn't lose any flex.
If you have samurai packs, then you will have to find a spring pack that has 2" wide leafs.  There are some CJ springs that are 2" wide.  And CJ springs have a pretty good arch to them.  So that would be something to look for.

76 or newer cj 5 -7    ....Boxcar...

so even since they are pretty flat can you do the trick where you flip the stock springs over?