Hi guys

I have a 67 Camaro and when I go over a bump or dip in the road it rubs on the left hand guard. Could this be a defective shocker?

 

after inspecting the suspension more closely I found this nut installed in the middle of the coil spring. Has anyone ever seen this before? Is this an attempt to stiffen the suspension up?

 

That's a coil spring jack/expander, not really good for the spring. To install, you put it between the coils and turn. Yes, it's an attempt to stiffen the coil, to compensate for worn out sagging springs.
Given that you're getting rubbing (what is the "it" that rubs btw), nice new springs are in your future.

 

I meant the tyre rubs on the guard

 

so if I was to take out this jack/expander would it make the problem worse?

 

Yes, the front will sag more in front without it.