Restrictive Mufflers

There are a lot of excellent points in this thread regarding mufflers and balancing flow with sound qualities. The first poster pictured a muffler design we used that was about 10 generations back (14 years). It served the market well with a reasonable exhaust flow/exhaust note and lasted for many years without coming apart even when being abused. Our most recent ACM-912 design (pictured) are for those wanting excellent flow and sound control that sounds close to factory. The ACM-912 mufflers have replaced these earlier units. For those wanting all out performance we have the "Stainless Magnum" series muffler which is similar to the Ultraflow and Magnaflow straight through designs but these , like most similar designs can resonate under load and certain rpms. A few issues that face those of us in the exhaust industry is marketing a muffler that is not too loud in the passenger compartment, flows reasonably well and fits properly.