You would want to raise the tank at least. I know mine would drag in the stock location.
I think you can lay one without the use of spindles, if using 17" or smaller wheels....if you set everything up right. I still need to flip my lower ball joints.
If using the stock front leaf spring mounts for a link bar, or using monoleafs, you may want to drill a new hole higher in the mount. My monoleafs had drag marks on them....not good, glad I changed to a four link.
If you are doing a forward four link, you can relocate the stock gas tank to behind the axle( on a standard cab, shortbed ).
Here is a thread from another forum with some good photos of the rear. Pretty nice set up.
http://www.blazinlow.com/forum/showthread.php?s=&threadid=60317