Stepped headers merge into a true reverse-cone megaphone muffler 1-3/4" headpipe steps up to 1-7/8" into the collector to increase flow and improve performance 4" muffler body with billet end cap Removable spiral-core louvered baffle included includes mounting hardware Includes O2 sensor port plugs Heat shields included Made in the U.S.A.. EXHAUST RR HS 86-11ST BK