Automotive industry is always struggling to comply with more and more restrictive emission regulations and the trend has been to employ engine materials that can allow higher combustion pressure and lighter design. Compacted Graphite Iron (CGI) is a class of materials that can allow this, but material and mechanical properties may largely vary within the given specification for CGI. Therefore there is a need for a fast and reliable method for classify CGI according to its properties. Impact Acoustic Testing (IAT) method of inspection measures the structural response of a part. Its volumetric approach tests the whole part providing objective and quantitative results. The aim of this paper is to demonstrate that it is possible to distinguish the test objects’ mechanical and material properties provided that geometrical dimensions are not varying. The results show the potential and limitations of this method in the given application.