Exhaust noise

You have to make the branch resonator installing it yourself of you could have a muffler shop make and install it. You have to first know the frequendy of the drone. You can calculated it but I just measured it with an app for my Andriod phone called FrequenSee - Spectrum Analyzer. Then instead of using an equations to calculate the size of length of the pipe I used this site http://www.diracdelta.co.uk/science/source/q/u/quarter wave tube/source.html . You have to have a flat cap/end on the end of the resonator. It won't work if you crimp it down and weld it. A muffler shop tried that for a guy and it didnt' work.

Look at this post, http://www.forabodiesonly.com/mopar/showpost.php?p=1970058090&postcount=68 , to see where I put my resonators on my 67 GTS. If you look at the rest of the thread you can see my plots showing the drone frequency.