Don't mount your engine in the jaws of a vice and you'll be ok.

Most people cut a notch in a 1 X 6 and bolt them down. You can nail or deck screw the 1 X 6 to a saw horse.

There are a number of test stands available on the market but you have to screw all of them down to a work bench or saw horse.

I always run my engines on the stand before I mount them on the plane. I like to have everything set the best I can when I go to the field. That way the vibration has settled down too.

Enjoy,

Jim