This tensioning device was designed to go with any Adjustment Arm. It is available here by itself for mounting on your adjustment arm. It is designed to be used with out having to make any modifications to the arm, as shown below.
You don't need to alter your adjustment arm but you do need to have a bit of spare adjustment available to mount this tensioner as shown above. Like shown it wont work if your alternator is already at the end of its travel. (However click on the "additional information" tab for one creative solution to that problem)