WCFab’s 2017-Current Duramax Billet Exhaust Manifolds with EGR Riser Flange replace the restrictive factory cast parts with high-strength, TIG-welded high-flow billet steel components designed to enhance exhaust flow characteristics, improving turbo spool up, lowering EGTs and increasing power and economy. These manifolds are exhaust port gasket matched and internally divided for optimal flow with OEM or ported cylinder heads. Outlet locations allow full compatibility with OEM style up pipes and are designed to be paired with WCFab’s 2” Stainless High-Flow Up Pipes (sold separately as part WCF100624) for optimized performance. Includes new gaskets, ARP 12PT fasteners, and assembly lube for easy install (up pipe fastener kits sold separately). Finished in Black Ceramic Coat rated for 2000ºF. No tuning required.