Look no further than Early Classic Enterprises (
ECE), as they will have everything you will need.
Check out my build thread in my signature for the install of a 4.5/6" ECE drop kit.
One thing you will need to consider.... if you are wanting a 2.5" drop in the front and decide to use a spindle, you will need to upgrade to disc brakes. Don't worry though, as this is covered in my build thread as well.
Just click on Blank Slate, and let me know if you have any questions.
Also, once you get the kit on, you will always want to go lower.