Tell the spring shop you need 9/16" by 18 round u-bolts, 3-5/8" wide by 10" long if you do a 2" drop. I did a 1-1/2 inch drop on mine so they are only 9-1/2" long. I only did a 1-1/2" drop because of the difference between the front and rear fender height. If you go a full 2" in the rear, it looks lower than the front even though it isn't. It's all a matter of your personal preference though. Either way, you'll be happy.
If you want 1-1/2" blocks, here is the drawing I made so the local machine shop could make them for me. (about $30)
great info, keith...thanx