Hi all
I asked this question some time ago on the forum and received a Post that identified a cone shaped perforated insert.
I tried this making one at the local engineer shop it does quiten down but changes the sound to whistle like sound. Perhaps someone may Post the site again ( Exhaust manufacturer in US)
Perhaps a purchased one from the manufacturer may have a different sound and reduce the noise dB level.
Cheers
Bernie
Bernie Knight
Mt. Gambier South Australia
Driving in the sun