Review on Flowmaster 53553 Big Block Muffler by Shawn Reiter

Fits a 2013 Chevy 2500HD 6.0L with Long Bed and Standard Cab. Length, offset orientation and inlet/outlet diameter are perfectly matched. The 2500HD will have some differences in exhaust layout between the cab and body layout, but this is perfect for the long body of the standard 6.0 liter cab. 2011-2014 everything should be the same. I cut about an inch in front of the muffler and about an inch and a half from the rear hanger behind the muffler outlet. This muffler was worn directly on the stock exhaust pipes. This Flowmaster is a few inches longer than stock, which is good because it fits over pipes. I used ribbon clamps on both ends and got a good tight seal. If you cut it right you can easily weld the stock muffler on or maybe clamp it down. The sound is good - be aware that this is a 3 chamber Flowmaster, not a 2 chamber like the Super 40 or 44. If you want a REALLY aggressive sound, go for the 40 or 44 (or 10). It's definitely a "muffled" sound - definitely a nice rumble, but not that bellowing guttural tone. It can be fun at times, but it will probably stop being desirable at some point. In standby mode, it almost does not differ from the standard. Step on the gas and it will rumble nicely. Nothing bothers the neighbors. It's a bit louder than the original at startup until it goes to idle. If you don't care about the exhaust sound, you probably won't notice any difference. At around 1300rpm there's a little buzz if you're in the right gear and applying the right amount of throttle, but most of the drone's range isn't.