Custom build your exhaust or turbo manifold with high quality Aeroflow components. Aeroflow’s CNC header flanges are manufactured from 9.5mm (3/8”) thick mild steel. They are precision-cut to meet your ports, reduce warping, and prevent leaks. The Aeroflow header flanges are offered in a variety of header flange sizes and shapes to mate your cylinder heads and headers/manifolds to meet your exhaust building needs.