An exhaust manifold for an internal combustion piston engine with a row of at least two cylinders inclined from the vertical. The exhaust manifold has plural exhaust stack assemblies and a manifold plenum with an outlet. Each of the plural exhaust stack assemblies comprises a leader pipe and an exhaust connector, with a first end of each leader pipe being joined to a first end of the exhaust connector of the exhaust stack assembly, and a second end of each exhaust connector being joined to the manifold plenum. Each leader pipe is joined to a manifold flange that is adapted for joining to the internal combustion engine to receive exhaust gases from the cylinders of the engine. Each leader pipe is joined in a vertical plane to the manifold flange at a first angle so that the plural exhaust stack assemblies are approximately horizontally oriented when joined to the internal combustion engine, and each leader pipe is joined in a horizontal plane to the manifold flange at a second angle inclined toward the outlet.