Will I break this crank?

Your Scat 9000 stroke crank will work fine with your build. They would not sell those if they were going to twist like a pretzel.

Where you are going to run into trouble is when you start giving it the shot of NOS. Daily Cruiser and Once in a While take a run at the Track.
That NOS is going to turn up any shortfalls of any type of engine you build.

360 Crank.jpg
Got to stop and think what you are really going to use it for. Apply common sense as needed. You will be fine.