[Power Hungry]

I've not seen anything to indicate that running on a dyno is any more dangerous than running on the street, provided that precautions are taken to provide adequate airflow for cooling. The one thing I will say is that people will sometimes tend to push a vehicle harder on a dyno than they will on the street and that may be the cause of some engine failures. However, in 15 years I've never personally witnessed an engine failure on a dyno.