let me see. There is a tool that fits on the pulley opening. Look close and you will see the shape of a big hex in the middle of the pulley. You place the big hex type tool in there and then a pip can fit onto that. Then drape the pipe over the front brace. That will stop the rotation.
I opened the bottom and took out the windage tray and jammed a crow bar up into the casing to jam the crank shaft- that stopped the rotation. I won't use that method again it was scary.
If you open the bottom get a couple bolts and bolt the flywheel bottom to trans casing bolthole. The flywheel and crank will be inhibited.
Oh, when I finally stopped the crank from rotating I had a 1/2" breaker bar and a 4 ft 1.5" pipe sleeved on top of that. Then I remember pushing down with all my weight. When the bolt finally gave I got faced. What a loud sound, not like a .62 magnum but certainly a .45 cal. I got up and laughed at how nervous I had been throughout. Next time I'll be rarin' to go!!! KICK OUT THE JAMS!!!