I would stay FAR away from the Mcgaughy's leaf springs. I had the exact same kit on my truck. I had terrible wheel hop so I bought a DJM flip kit and when I swapped out the leafs they were BENT.
If you want 4" drop leafs I would get the belltech ones.
Remember you get what you pay for. I learned the hard way.
EDIT: Here's a link to pics of my truck with the Mcgaughy's 2/4 drop...
Lots of Mods!! 56K Beware! It's the forth pic down.