Leaf spring questions?

[timpage]

Im pretty new to understanding "leaf spring tech" lol. I have some questions to figure out what I have though. My truck: 1987 Chevy V-10 with stock springs front and back plus an add-a-leaf front and back added by a prior owner(questions will deal with the rear, so have 6 leafs total in the back w/ the add a leaf).

I've learned enough off the internet to be dangerous, but not enough to understand what I'm after.

My questions: What are the rear leaf spring specs supposed to be? I ended up with a set of springs I got for free. The length and pin location are the same as my truck (52 inch main leaf length, centered pin, 2 1/2 inches wide). However, this pack has 7 leafs, and an approx. 6 1/2 inch free arch. There is no info stamped or painted on these springs to know brand, if they are lift springs, or what they are for officially. I am wondering IF I were to mount these springs on my Chevy, would they lift it in the back, and if so approx. how much? Im not really looking to lift my truck much more than the inch or two I get from the add a leafs, would be more interested in slightly more load capacity with the 7 leafs vs. my current 6. Hope this makes sense lol.

Anybody have some insight for me?
Thanks,
Tim