I am going to do exhaust on my 67 vert this winter, replacing headers with long branch cast iron. I'm also going to replace the missing X brace. I looked at the Pypes site and they sell aluminum spacers to you can supposedly fit the 2 1/2" X-pipe with the x-brace. I would rather find exhaust that will fit the stock config. Another place to look is Gardner at:

http://www.gardnerexhaust.com/homepage.html