On my blue Challenger. I have since this photo turned the turn downs to face inward towards each other to cut down on the dust at shows. No carbon monoxide issues with driving all over on the street.Dumping exhaust under the car is a good way to get Carbon monoxide poisoning inside the car an a cruise.
From Google:
Google Search
I agree, these cars are far from airtight!CO is odorless, colorless, tasteless .
If you are lucky you may start to get a headache as a warning, if not, just unconsciousness.
Keep the windows rolled down.