[thstone]

My thought is placing all of the torque on the crank keyway may not be the best practice.

It might be better (per the instructions) to have the torque force carried on an external bolt that transfers the load to the engine case to avoid loading up the crankshaft and/or drivetrain.

I have installed 3 UDP's and used the bolt to hold the pulley each time. I can't say if the other approach would be ok to use or not.