Over heating!
Scared to run it on the road
You need to test your cooling system. Idling in a driveway (most likely with the hood open) is not a test of your cooling system.
Your hood is part of your cooling system......
Go drive it on a nice clear road at 45+ mph and see what it does.
If it runs cool at 45+ (or cools down at that speed), you have an airflow problem.
If it's still hot and doesn't cool down at a steady 45+ mph, you have a flow, capacity or tuning problem.