BORLA(r)'s CrateMuffler(r) is the world's first muffler purpose-built to optimize the sound & power of crate and custom built motors. The mufflers are directional. The outlet can be identified by the mounting bracket welded to the endcap. This muffler is tuned for the Chevrolet Small Block 350/ 383/ 406 CID V8 engine family. The directional design provides the classic S-Type sound and will dramatically reduce, or eliminate drone on specified applications. Add resonator 400939 to attain the mellow Touring sound level. Muffler dimensions 3" Offset Inlet/ 3" Offset Outlet 4.35" x 9.10" Oval, 14" Long Body, 19" Overall Length. Built from premium T-304 stainless steel, superior to T-400 series (such as 409), to give you the absolute best in performance and durability. Precision computer numerical control (CNC) manufacturing ensures an accurate fit and best of all, BORLA(r) stands behind every CrateMuffler(r) with a Million-Mile Warranty. Just what you'd expect from the world's most experienced (and most winning) exhaust brand.