WOW Dan, I'm blown away at the information you supplied. This is pretty close to what I have. The difference is that the truck has a 4 speed transmission that didn't have a u-joint on the tail like most 3 speed transmissions do. The extension assembly went directly into the transmission and was bolted to a cross member support that had the ball assembly attaching to the torque tube. So my 125 1/2 long bed truck still only has 1 ball assembly on the drive line(propeller shaft). This might be a unicorn assembly, that's why I posted here as I haven't been able to find the exact parts books. I'm going to keep digging through old books, maybe GMC used the same setup for 47 or later trucks. It will take me a little while to clean the assembly up and get it listed for a fellow Bolter to use. Thank you very much for posting what you found. Andy
