I produced the soft mounts (back in the 88-91 time frame) now marketed by Sullivan Products (shown in post #10). Don't use any locktite on the screw threads, either on the stud/plate isolators into the blind nuts/firewall, or the screws that clamp the rear mounted plate to the rubber isolators (the external tooth star lock washers provided work perfectly), as you'll never be able to remove the isolators from the blind nuts if you do! I never had one come loose, nor did anyone tell me that they did either. It was a very simple yet robust system that worked quite well at isolating engine vibration from the airframe.

Jerry