I'm pretty sure that ORU or OR-something or other makes a shackle flip for those Chevy's. And I agree with Hus, for the love of god please don't stack it.
Pretty sure yours are 56' springs, while a half ton is 52..
So unless u plan on moving the hangers than i'd stick with the 56's. I just wouldnt run lift springs... mkaes it rougher than hell. I will get a flex picture of mine its a pavement pounder but has the most travel i can:P
i was meaning lighter springs to compensate for the air ride I wont necessarily need one ton springs with air ride...3/4 ton yeah and a leaf or two in the front woukd do aswell as 3 or so in the back.
Also let me know what kinda things you need... i got the part numbers for longer flex lines front n rear. Was a pain for them to find them for some reason.
If u ever have trouble finding something.. some of them are pain. I've gone through it all