I work on class 8 trucks and run them on a dyno. We chain them down for just that reason, and damn sure don't stand on the side.
You haven't lived until you run a truck up to 2000+ rpm, thirteenth gear, pyrometer running over a thousand degrees, 28 lbs manifold pressure, 600+ horsepower and 2000 lb/ft torque. You can smell the rubber and the howl just cuts right through you!
God I love<a href"http://www.peterbilt.com/index_alternate.asp"> trucks!</a>