Borla CrateMuffler Big Block Mopar 383/413/426/440 2.5in Offset/Center 14inx4.35inx9in Oval MufflerBorla CrateMuffler Big Block Mopar 383 413 426 440 2. 5in Offset Center 14inx4. 35inx9in Oval Muffler BORLA(r)'s CrateMuffler(r) is the world's first muffler purpose built to optimize the sound & power of crate and custom built motors. This CrateMuffler(r) features the aggressive ATAK(r) sound. The mufflers are directional. The outlet can be identified by the mounting bracket welded to the endcap. The directional design provides custom sound, tuned