You shouldn't have needed to expand the slip joints any. Start in the back and follow the directions. I've installed 2 complete systems, I only had to trim the rear of the headpipes about an inch on my 69 R/T. The system on my Patrol car in my avatar fit without any cutting..
And yet, I had several joints that were too tight to slip together which is why I went to the muffler shop. I also started at the back just as the directions and videos specified.
