It will work...just depends. On some engines with a flywheel you can have degrees marked on the flywheel. But you can use a dial indicator to make sure "O" Top dead center is marked right. The point I was making ...instead of using a spark plug "stopper" you can use a dial indicator in it place. Of coarse you would use the other gizmo's if you like.! Ha! If you want to try something interesting, use a timing light while engine is running. Some of the stock mag systems do have advance built in...like on my MB290. You can freeze the prop and read the size on it!!! Capt,n