Here is the part number off of my one piece driveline if it helps ya out. 23251132. I googled it and looks like you can get them for about $450 from GM parts giant. It came with the 1480 u joints so i had to upgrade the rear yoke.
Thats some nice stuff. I am hoping to hit the 11's next spring with the cheaters. Going to swap out the converter to the Goerend k this wintwr as well.