I have Fentons on a 55 1st series 3100 with the original 235. I am also lucky to have a good muffler shop close that bent both new pipes back from the headers. I wanted to hear the exhaust so I had them use some pretty much straight through small glass packs. I love the sound until it hits around 2500 rpm, then it takes on an unplesent rattling sound. No big deal since I usually keep it under 2500 rpm anyway. I have been told that an X pipe would solve this problem. Just a thought. I am sure different mufflers would also help.
