Hey Bo,
Thanks for all the info!
Looks likes the Silence-Aire muffler was the one. I imagine finding one of those would be a bit difficult these days. At one time Macs Products made a muffler that looked similar to the Silence-Aire and Mini-Vox. Probably also hard to come by. I'd be very happy with a factory Webra muffler if I can find one. If not, someone told me that the HB mufflers will fit a Webra and MECOA still sells those.
RG