The plastics might hold up these days but when the motor is running, I'm afraid you'll just be looking at the flood of your lubrication system...maybe for those trailer queens!
I've seen those before. Surprisingly, you can see the valvetrain moving. I figured it would be like smalls said, all oil, but it wasn't. Seems like they were on an open engine drag car, they zoomed in on them, very cool looking. Guess they'd be good to see if you had a rocker wobbling.....