68 single exhaust is complely different to the 67 version. 68 the muffler and pipes extent back in a straight line where 67 is 90 degree into the muffler and 90 degrees out. The y pipe also is different to a 68. The parts are not interchangeable without completely removing the system from manifolds to tip. I would also assume hangers were also relocated with the different positions. I have a nos exhaust waiting for me to ship. Its 91 inches long, 1 piece and runs from the end of the Y pipes to the tail. I'll get the pic uploaded and drop it in here.