The article presents the results of bench tests of a single-cylinder diesel engine (dimension 7.5/6.0) with different configurations of the intake manifold. A brief description of the stand is given. The modernization consisted in the use of a section in the manifold with cross-sections in the form of a square or a triangle. The power characteristics of the diesel engine in two operating modes are presented. It was shown that the profiling of the intake manifold leads to an increase in the diesel engine power up to 17%.