409 Stainless steel Magnum series mufflers are used when unrestricted full flow is required. Magnums are more aggressive-sounding without being obnoxiously loud. The exhaust note is aggressive under load and at about 22-2800 RPM there could be interior resonation, as with any high-performance muffler. This may change depending on cam profile, induction and gearing. At cruise the Magnum muffler is mellow in tone with minimum interior resonation. An excellent choice for a 273 Hi-Po A-body and many B-body applications. These have an 18" ( A-body) 20" (B-body) case length and come in 2.25" inlet and outlet. When ordered with an Accurate Exhaust exhaust system the proper inlet/outlet sizing is test fitted to the exhaust system.
To get an idea of the sound check out the video below..........