Anyone else?

[JTS71 Mach1]

The ones that are available here are like a dual unit in one.  There is like a 'choke flap' just inside the inlet that allows the driver to divert the exhaust through the sound absorbing material or allow a straight through with minimal effect.

Good for scaring neighbours or keeping the local traffic police happy! 

Sounds perfect!

[1969_Mach1]

Unfortunately, no afterburners or sonic booms in my collection...yet.   I plan on using a slightly louder muffler on the Fairlane compared to my Mustang.   So I am open to recommendations for a good sounding, deep tone, muffler, but one that will still allow me to hear myself think and carry on a conversation when I am driving   

Pricey, but Borla has some nice mufflers in their XR1 series.  All of Borla's mufflers are a straight through design with no baffles or chambers.  I use their Pro XS series on my Mach 1.  Similar sound but a little quieter than the XR1 series.  I also like the sound from Flowmaster mufflers.  But I didn't want my Mach 1 to sound like every Camaro and Chevelle running around in my area.

https://www.borla.com/products/xr1.html

On another note, camshaft and compression ratio have a large affect on exhaust sound.  The earlier the exhaust valve opens the louder the "pop" you will here from the fuel mixture firing in the combustion chamber.  Higher compression ratios also increase the volume of exhaust.