Unfortunately my bed is on and I realize mine is 53 not a 63 so differences obviously apply, but there is little to no room to run any kind of pipe much further back than maybe 6" behind the cab with the php setup you get with a 4-link from people like TCI. That's just my experience installing one.
This is an edited photo to give you an idea:
http://i16.photobucket.com/albums/b8/robin58/illustration.jpg Obviously a different 4-link and a different php will result in different needs/problems. However I was specifically referring to the one that comes with the most popular kits sold by retailers dealing with our older model trucks.
