I have a 2003 Z71 (1500, Ext Cab) and I use this truck off road all the time. I only have 33" tires (no lift, they clear fine). But I want a solid axle. I keep hearing that it's a weak truck, but I have seen them run 40"s w/o soild axles, just a lot of body lift. I want to run 38"s at most, I just want the added stregth and travel of a SA. If there is a kit, or if anyone has an idea of where to start I would appreciate any help I can get.  

I have done alot of researching on this subject and for your year model you might start with Cage Offroad. They offer a very well designed kit, but it is a coil kit with 2-link suspension. You could also try:
Offroad Direct
Offroad Unlimited
Sky Manufacturing

These are just a few. hope it helps you.  

Thanks! Offroad Direct makes a kit for it. So now if there are any suggestions for which axle/diff and so on that would be awesome. There site says the parts list isn't complete so all the little bits aren't on it. I'm pretty much lost in this stuff. I appreciate it very much.  

And what about front and rear gearing? I'm not 100% of what it is stock (3.73?) but I know they have to be the same. And I plan on using a Ford Dana 60 up front, so will the factory rear end be strong enough? Maybe I should just wait and see what they do with this new Z71 project truck... the Marine Corps needs to give me a raise!

And another thing... I have push-button 4x4. Got a feeling thats a problem  

You can get bigger half shafts for the front and stronger knuckles and all that but don't run any of the without changing the joints as well..... I installed bigger shafts, new gears front and rear all new u-joints throughout and just rebuilt the transfer case with stronger gears and moser axels in the rear. CTM Joints are the only way to go in the front. If you don't use bigger joints then there is o reason to do bigger shafts since the added stress will just snap the stock joints. Hope this helps you out.... By the way it's a lot cheaper and easier to just work with what you have!!!  

youd be better off with a small lift on the stock suspension, beefing up the front axleshafts and regearing with 35's especially if your goign to be doing any highway driving, you'll save on fuel and power because if you have that stock ten bolt rear its not going to like 38's  

the427chevy:
youd be better off with a small lift on the stock suspension, beefing up the front axleshafts and regearing with 35's especially if your goign to be doing any highway driving, you'll save on fuel and power because if you have that stock ten bolt rear its not going to like 38's

It is not going to be very happen with 35's either. Many seem to have trouble under standing that modern GM 1/2 ton trucks are built pretty light and no where near as tuff as the old 87 on back ones. Back then 1/2 ton and 3/4 shared same front axle except for bolt pattern, today they do not. They shared same basic frame too.  

dude i agree with snoman, the new ifs are not meant to be lifted that much or to handle huge tires unless it is only a mall crawler so try the sloid axle swap, the rear is leaf right so it should not be to bad to go ahead and swap. hey snoman, the few times i get on for help i just read everything else cuz i like cars, and trucks. how did you get all this stuff in your head figured out, i know most of it due to my dad but i cant just remember like that. i have to think forever on it but i am only 19 too, you are cwazily smart, thanks for the tips on stuff, i actually like reading here cuz i actually learn.lol  

"Mall Crawler" that's cute!