Crank pully as in what does it run? I dont know those motors. Is it a timing belt pully or just an aux pully?
If it isnt the t-belt I dont see the dier need to use 10.9’s… but if its the timing belt, and it make some srs power I guess I would want the strongest bolt i could find.
Also if your swaping to a new style why not use an OEM bolt?