Originally Posted by HammerZ71

I've never been able to get actual CFM rates on ANY Magnaflow mufflers. They don't publish them, but I'd imagine from cut-outs I've seen of them, they would be good flowing.
The CB Extreme has a published flow rate of just over 500 CFM, which is on the better end of the scale, about the same as glasspacks.
Stock is somewhere in the mid-300's which is also about where the "Flow"masters are for comparison...