Our intake manifold flanges for the 5.9 Cummins are CNC machined in house from 6061 aluminum Key Features: - They are designed to fit a 3.5” OD tube and are multi axis machined to ensure proper air flow - This flanges are perfect for anyone with aluminum welding skills that wants to build their own custom intake/cold side intercooler setup - At over ¾” thick , you can be sure that this flange will maintain flatness and not leak - Each flange has a 1/8”npt threaded port for easy installation of a boost gauge or to inject water/meth - This intake weld flange is designed for years 1989 to 2006 Compatible with: Cummins, Engine & Engine Parts