Abstract: An elongated hollow body closed at its opposite ends is provided and constucted of high heat resistant metal. The body includes an exhaust gas outlet opening outwardly of one side thereof centrally intermediate its opposite ends and extending in a direction along a path generally normal to and intersecting longitudinal center axis of the body. A plurality of short tubular exhaust gas inlet stubs open outwardly of the opposite side of the body and are spaced therealong from the closed ends and on opposite sides of a transverse plane centered relative to the outlet. The stubs include outer end mounting flange portions supported therefrom similarly inclined generally 20.degree. relative to a plane substantially normal to the stubs, the effective length of the stubs being generally equal to the width thereof.