Hi I am new to this forum and looking forward to hopefully getting some help here. I recently purchased a 67 Firebird 400 convertible and am going to either enhance or replace the exhaust. Those familiar with the Firebird 400 exhaust will know what I speak of with regard to the factory exhaust setup Pipes exit separately from each manifold into separate resonators. Pipes then continue separately over axle into a single transverse muffler where exhaust exits into 2 separate tail pipes. I'm mainly a GTO guy. GTO is much simpler and always sounded great to me. 2 pipes, 2 mufflers. They never meet. To me, this is true dual exhaust. Meaning you stand behind it at idle and hear each pipe firing from each side of the engine separately. So regrading the transverse muffler in my Firebird, I'll try and express my concerns using the concept of stereo. I'm concerned that the transverse muffler ruins the "stereo" sound of 2 separate channels individually delivered to the listener giving it depth. Meaning the sound that comes out in stereo from the engine then gets put into one speaker (the transverse muffler) and then splits into "dual" speakers is not true stereo...you're hearing the identical sound coming out of 2 speakers. When I listen to my Firebird that is what I swear I hear....at least what I THINK I hear. The same sound coming out of each pipe giving it a dull fake sounding dual exhaust. My GTOs I swear I could hear the rapid firing of the cylinders back and forth from side to side and it sounded great. Reason I ask because I am thinking about moving away from this factory setup (with the transverse muffler) and to a more GTO like completely separate duals system. Am I imagining what I describe, or is my theory correct? Am I overthinking this? I would like to keep it as original as possible (it is what we might call a survivor) and would like to be as informed as possible before I change from factory.

You can delete the transverse muffler and set it up with just the mufflers and tailpipes if that would make you happy. Personally I prefer quiet.

That's what I'm trying to find out. If my suspicion is correct. That a transverse muffler actually defeats the purpose of "true" dual exhaust. I might just not know enough about transverse mufflers.

The main point of dual exhaust is to increase the cross sectional area of the exhaust flow. So you still have the cross sectional area for flow but the transverse muffler will restrict the flow somewhat. If you want to cut down on the noise you have to accept the flow restrictions of mufflers. Otherwise just run open headers. Cars don’t necessarily run better with less exhaust restriction. Depends how the motor is set up. The x-pipe manufacturers swear that improves performance.

With the exhaust crossover in the intake manifold, is there really separate exhaust for each side anyway?