For a street car solid motor mounts are not desired. On a Turbo Omni I installed a motor strap that was solid on both ends and ran it for two laps at Texas World Speedway in Collage Station. My GOD was it rough and transmitted every vibration. Changed it before the races started to a solid at one end and cut off shock mount on the other. That was just a little more then stock and very livable. It helped at shifting down at 85 mph at the end of the straight a way.