4B11 EVO X Head Flange (1.25″ Sch10/Sch40)

Build a high-flowing, bulletproof turbo manifold for your Mitsubishi Lancer Evolution X with our 4B11 Head Flange.

• Proudly Designed & Machined in the USA: Precision CNC machined in house to guarantee exact bolt hole pattern alignment and flat sealing surfaces for the Mitsubishi 4B11T engine.

• Ready for Fabrication: Surface-finished and deburred so you can jump straight into tacking, fitting, and TIG welding your custom runners... saving valuable shop prep time.

• 1/2″ Thick 1018 Mild Steel: Extra thick plate construction resists warping, distortion, and thermal fatigue during intense welding heat and harsh track thermal cycles.

• 3D Machined Port Transitions: Features 3D CNC machined ports that seamlessly taper from the factory 4B11 cylinder head port geometry straight into standard 1.25″ Sch10 / Sch40 weld elbows or pipe.

• Unrestricted Exhaust Velocity: Smooth port transitions eliminate sharp steps, reducing backpressure spikes and maximizing turbine wheel response for faster boost spool.

Precision Foundation for Custom EVO X Manifolds

Welding a custom manifold onto a thin or poorly machined head flange leads to exhaust leaks, warped flanges, and restricted airflow. Our 1/2″ 1018 steel flange stays flat under heavy welding and extreme anti-lag exhaust gas temperatures, while the 3D-machined port transitions ensure your 1.25″ runners align perfectly with no restrictive overhangs. It's the ultimate starting block for a record setting EVO X manifold build.