Remove some of the leaf springs in the front and have your front axle dropped. For the rear, use lowering blocks. I did this on my 48 and it looks awesome.
Dave Mann in Arizona can drop your stock axle for you and he does a beautiful job. His website is:
http://www.roadsters.com/axles/ It explains how an axle is dropped and also provides price estimates.
This is "generally" accepted as the traditional way to lower your truck without getting into Mustang II's, air bags, subframes, etc.
