[Maroon 5.0 LX]

You really only need a big heavy screwdriver or piece pipe. Stick it down to the left of the pulley on the tensioner, push against the pivot and that will release the tension. If you have the right size belt and the routing decal is still under the hood, it should work pretty easily.

Now, I'm not sure you can do this with the supercharger on your car, but I just went down to my garage and the above worked fine on my stock '89.