For vehicles that employ a front engine and front wheel drive (FWD) system with a transverse engine layout, the mounting insulators for installation of the power plant require the following five performance items: ➀ Minimization of shock transmission from the power plant to the vehicle body when accelerating or when changing gears. ➁ Minimization of engine vibration transmission when the engine is idling. ➂ Reduction of vertical vibration of the vehicle body due to input from the road. ➃ Reduction of unfavorable shock resulting from the delay in movement of the power plant against the vehicle body due to lateral acceleration exerted when steering the vehicle. ➄ Blockage of noise transmitted from the engine and transmission.Up until now, there has been no effective means of adjusting the mounting insulators so that all five required performance items can be satisfied at the same time.This paper describes a method for optimizing performance items ➀ to ➃ above for handling low frequency vibration in a power plant mounting system supporting on a torque roll axis. The focus of this report is on the technology for minimization of shock transmission from the power plant to the vehicle body. The following points will be covered: (1) Theoretical analysis and verification through experiments for vibration. (2) Determination of the mechanism for shock transmission from the power plant to the vehicle body. (3) Minimization of shock transmission from the power plant to the vehicle body (4) Presentation of required performance items of mount stiffness for reducing the vibrations mentioned in ➀ to ➃ above. (5) A calculation method of the mount stiffness for achieving the simultaneous optimization of all four required performance items, and the results of its verification through experiments.