Cast aluminum alloys are increasingly being utilized by the automotive industry for manufacturing chassis and powertrain components to reduce vehicle weight and consequently increase fuel economy and reduce emissions. High pressure die casting (HPDC) process provides tremendous cost saving opportunities in manufacturing these components. Development of Virtual Casting tools for HPDC aluminum will lead to fast prototyping and tooling, thus fast final products with reduced cost. This paper describes the simulation of microstructural evolution during casting process and prediction of yield strength after heat treatment of an HPDC air conditioning compressor housing (A/C housing). The prediction can be used to design and optimize casting component and process.