Cool old vintage shop equipment, what you have?

I've used it several times, but I've got no old time experts around to train me on it, so I've relied on Sun instruction books. Needless to say, unless the car has an obvious malady, I'm not an expert on it.

What always throws me off is how unstable all the lines are as the cylinders fire; in the pictures in my manual, the lines are always static. :)