Big 3 + Catch Can = Problem?
 

I have a catch can that I am going to install on the block with the supplied bolt. I have been researching the Big 3 wiring upgrade, but noticed that the block to chassis wire uses this same location.

Would there be a problem just putting the ground wire under the catch can mounting bracket?

I can't imagine that causing a problem. Be sure to clean the area with a wire brush to ensure the best ground contact.