A radial engine-generator includes an electric power generator and a radial engine. The radial engine-generator can be a mobile and portable unit, and is employable as a primary or back-up source of electric power at data centers, manufacturing facilities, electric vehicle charging stations, medical facilities, telecommunications, and residential neighborhoods, among many other applications. The electric power generator and radial engine are coupled together. The radial engine includes, among other components, multiple cylinders, multiple cylinder heads, and multiple overhead camshaft assemblies. The overhead camshaft assemblies are located at the cylinder heads and each include one or more camshafts. The camshaft(s) receive rotational drive input from a crankshaft of the radial engine. In certain implementations, camshaft carrier assemblies can be provided to support components of the overhead camshaft assemblies.