I recently got a 01 Z28. It seems to bottom out in the rear. I put on new shocks and noticed the coil springs are red color. I am guessing they are not stock? Checked the exhaust and it is not hitting anything. Am I going to need to put stock coils back in to get rid of this clunking and bottoming out type action when I hit a good bump? Thanks.

 

Get new rear jounce bumpers, oem/rubber preferably. Your axle may be hitting the frame without any cushioning.