SPC Big Bore 4.5 Stainless 2 into 1 for 2018-up Harley M8 Softail

4.5” High Flow Performance Cone Muffler with a Stepped Baffle from 2 1/4"- 2 1/2" Increases bottom to mid range torque and horsepower on all motors. Tuned properly it can accommodate 88" to 143" engines.  065 Stainless Steel Headers stepped from 1 ¾” TO 1 7/8” TO 2” at the collector Hand TIG Welded from Top to Bottom Machined Stainless Steel Header Collars 18MM O2 BUNGS with 12MM adapters, allows for stock or Autotune O2 Sensors  Complete hardware kit with everything you need to mount it up