Any problems putting 3’ exhaust on 70 Dart ?

I ran TTi headers and their full 3 inch X pipe system with Dynomax super turbo mufflers on my 70 Dart 360, no problems with the installation and I was very happy with the sound. It was reasonably mellow under "normal" driving conditions and whenever I stomped on it, it was considerably more aggressive, suited me fine.
Was it overkill? Maybe, but I had planned on going bigger when I did it.