Our new 409 Stainless Magnum series mufflers are used when unrestricted full flow is required. These have an 18" ( A-body) 20" (B-body) case length and come in 2.25" inlet and outlet. When ordered with an Accurate LTD 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..........
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 273 Hi-po A-body and many B-body applications.