Bought mine at Summit Racing, there are many brands stay with a top name to avoid issues. I think Amazon.ca or local speed shop. Karbelt or Performance Improvements.
Determine size
2-2.5-or 3 inch, electric or manual, remote or switch, round or oval. Most do not come with a stainless “Y” pipe. So buy a complete kit or by locally.
Custom muffler shop will install but most do not connect or run the wiring.
You can do this yourself or have a mechanic do this part of the hook up.
Wiring on my 65 was easy on a C4 it may be difficult.