My 1995 Z28 has had 9.5" and 11" front and back wheels with Eibach lowering springs for at least fifteen years now, and without issues. But lately, as I drive over rougher roads, my center console ,along with the chassis below, clunks and thumps as I hit shallow pot holes. I think it could be the torque arm. What could cause this?

 

If your car is an automatic then it could be transmission mount.Some dealers still have them,mine did in santa clarita, ca.It was $26.00.Hope this helps.

 

I was thinking trans mount as well. Not just automatic -- the setup is similar for manual cars and the part should be similarly inexpensive.

 

Also, subframe connectors help immensely on our cars, especially as they get older.

 

My automatic transmission has about 10k miles on its complete rebuild. I just raised the car and underneath I saw the torque arm bushing looks new, feels hard, and the trans mount might actually be new, so I am at a loss!

 

Did you try lifting the trans off the cross-member, to see if the mount was cracked? Sometimes you can't see the crack with the trans resting firmly on the mount.