Underdrive Pulley Install Help Needed

[Yellow986S]

I am unable to tighten down the pulley to 37 ft lbs and then the additional 90 degree turn without the pulley spinning with the bolt.

I have tried using a strap wrench, putting the handbrake up with the car in 5th gear, and also using a small allen key to try to hold the pulley in place.

Any tips or ideas on how to prevent the pulley from spinning to allow me to properly torque it down would be great.

Thanks