that was prob. it, my step dads brother had a z28 and took the front air damn out and at hwy speeds it also started to overheat...that was the first thing he told me not to do when i bought mine lol

 

Well it has been a couple of weeks and several hundred miles since I installed the missing air damn and everything is working great. It hasn't thought about overheating even on 90+ degree days with the AC on. Thanks to everyone for their help.

Steve