green48,
Look for a gm 1/2-3/4 ton 12 bolt from around the late 60's to early 80's.
This site calls it a GM Corporate 12-bolt. I don't have a width for you, but
mine fits great, has 6 lugs for the original wheels, and a 3.07:1 ratio.
The "How to Restore Your Chevy Truck" book has a picture of a red one in it somewhere.
