An opposed-piston engine includes an inline cylinder block with an open exhaust chamber that contains all of the engine's exhaust ports. Exhaust outlets open from the exhaust chamber through opposing sides of the cylinder block. A turbocharger is positioned on each side of the cylinder block and has an inlet closely coupled with a respective exhaust outlet. The exhaust chamber is divided into separate collector sections, each collector section containing the exhaust ports of one or more cylinders, and each turbocharger has a first inlet closely coupled with a first collector section and a second inlet closely coupled with a second collector section. The engine has a cylinder firing sequence which alternates between the cylinders in the first and second collector sections.