LS Turbo Headers (Up and forward) 1-3/4" 409SS GM 4.8/5.3/6.0L V8 Natural Finish Flowtech Headers are the perfect combination of quality and value. These "4 to 1" LS Turbo headers available in 1-3/4" and 1-7/8" tube diameters are an ideal design creating a compact package allowing a variety of configurations (Up and Forward, Down and Forward, or Down and Back) to be used as a universal fit Turbo header. Features: CNC Mandrel-bent tubes provide consistent tubing diameters for smooth flow and increases the cylinder scavenging effect and improves engine breathing Heavy duty 16-gauge 304SS (Polished Finish Only) and 409SS (Natural, Black Painted, and Ceramic Coated finishes) tubing for increased strength and durability 1-3/4” and 1-7/8” tubing diameters available for increased exhaust flow increasing performance and improved throttle response 3” collector for maximum strength and exhaust flow 7/16” thick header flange for a leak-free seal and maximum strength Premium aluminum header gaskets included 3” V-Band Flanges and Clamps are included Available in a total of four finishes (Natural, Black Painted, Ceramic Coated, and Polished) Bolt Size M8 x 1.25 x 25mm Brand Flowtech CARB (California) Compliant No Collector Diameter 3.00 inch Emission Code 4 Engine GM Small Block Gen III/IV (LS Based) Header Finish Natural Header Style Turbo Material 409 Stainless Steel Primary Tube Dia. 1-3/4 inch Product Type Headers Tube Material 409 Stainless Steel UPC 090127733028 Part Number 11535FLT