I enjoy the sound of Flowmaster equipped cars. I must be one of the few that have a "drone-free" set of mufflers. I have a 440/493 with a 292/509 cam, TTI 2" headers, 2 1/2 pipes with 42451 Flowmasters and full tailpipes. Simply put, I found the chart listed in that other muffler post quite interesting and it made me curious. My exhaust system is 8 years old but looks and sounds new. I am not looking to replace rusty muffers here, I was just interested in what the flow rates translate to in terms of power.