well we have a 65 mustang with a 289 and the muffler is origional and rusted through and it sounds really good. i have yet to find anything that sounds better. it is quiet when you are cruising but when you stomp on the gas it gets pretty loud. so i guess maybe try to find an old rusted out muffler.

 

I drove my nephew's 02 GT with stock mufflers today, and it is certainly louder than my 03 Mach 1 . I noticed the biggest difference in 4th gear at about 3K RPM. That sucker really howls at you at that RPM and gear.

 

The Mustang on Bullit is not a Mustang exhaust...They dubbed a gt40 over it..count how many times it shifts

 

Get flowmaster 10 series and dump em before the rear end. Quiet but really muscly at the same time, but HELLSA loud when you get on it and sounds likea NASCAR i would know my bro races em it sounds like his when I get on it. GET EM!