Years ago, in the early 1970’s after breaking a few and not thinking about running a bolt thru , my brother made a solid set. He took measurements and removed the rubber. He then took strap steel and welded it to the outside perimeter. I’ve used them to this day. Not something I would do on a street vehicle as you really feel engine vibration in the car. Solid engine mount be sure to use urethane trans mount...
Used these on 4 different FE motors from 12,11,10 and 9 seconds and it doesn’t affect the mount area