A composite material intake manifold cover includes braces integral to the outside surface of the cover to stiffen the cover and reduce noise and vibration associated with the cover. The cover has a flange around the periphery with a raised weld bead, the weld bead provided for welding the cover to a mating piece. The flange extends outwardly from the cover for a first distance over most of the periphery and a second distance to support the braces over the remainder of the periphery. The braces extend upwardly from the upper surface of the flange at the sections of the flange extending out the second distance and may be placed between adjacent intake runner ports. By providing portions of the flange extending out a greater distance, a more substantial brace can be supported, thereby improving the noise and vibration characteristics relative to conventional stiffening ribs.