Borla CrateMuffler Mopar BB 383/413/426/440 S-Type 2.5in Offset/Offset 14inx4.35inx9in Oval MufflerBorla CrateMuffler Mopar BB 383 413 426 440 S Type 2. 5in Offset Offset 14inx4. 35inx9in Oval Muffler Borla's CrateMuffler 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. The directional design provides custom sound, tuned for each engine family and will dramatically reduce, or eliminate