Sorry Phil but thats not quite correct. If you are driving up a hill and the engine starts to load up you change down. On a dyno they keep loading it up (in 3rd) until it it peaks. Rarely does anyone do this on the road. So weaknesses that are ok on the road can cause expensive problems on a dyno.
I was lucky, mine was only a blown head gasket. That was when I was young and stupid. 20 years on, after jusy spending over $6k on my engine there's no way it will ever be dyno'd. I dont know its bhp and dont care. Like me these days its built for comfort not for speed

I also worked at Orbital for a while and saw lots of blown up engines come from the test cells. They were testing but it did show me just how much damage can be done.
There are some great examples on youtube. Just search for dyno fire or dyno explosion.
Here's a taste
http://www.youtube.com/watch?v=q-04a-7Glng
Good luck Paul - hope it goes well for you.