Rear End Center Bump Stop
 

Is there a rubber reproduction one of these?

https://i.ibb.co/LvM3Ks1/20230226-124333-HDR.jpg

This is on my 77 Trans Am, but I assume it's probably a pretty universal part for many GM cars. Haven't been able to find one anywhere. I have new ones for each side, but not the middle. The one in that picture is 30-year-old polyurethane, and it's become hard as a rock.