Do you know how much lift the kit gives you?
You've got a few options you can go with. I'm thinking you will need 2" blocks, they make bigger ones but you will have pretty bad axle wrap.
Longer shackles will give you about 1.5" of lift. Look for Chevy lowering shackles from Belltech or Summit racing has their own brand.
Add-a-leaf, this will give you about an 1.5" of lift I believe but a stiffer ride.
These are the "cheap" alternatives to all new leaf packs with lift.