I think I know what you're talking about. My rubber buchings connecting the dogbone to the engine is shot so I was just looking here...looks pretty involved more so than I though. Special tools required and the engine neeeds to be jacked up and down not to mention alo of lube and torque specs.
Anyways,...in my 98 DeVille GM Service Manual, its called a Engine Mount Struts or Torque Struts. (I think....)
BTW its got a note in italics here says: NOTE J 28467-A Engine Support Fixture Required (fyi) anyway can't find a part number here, but its called Mount Stut or Torque Strut in this manual.
Looks like you gotta make sure its not preloaded before you mess with it and then once you put your new one in its goto be tightened to 60 NewtonMeters or 44 PoundFeet. Good luck! (did you try ebay using these keywords?)