Very informative thanks for the info!! Could this cause sputtering when going into boost at low rpms? Having a huge issue with this right now just didn't know if it could be related
.A couple of things here to note. The Gt500 and GT tensioners are different. Automatics are much easier on the tensioner and belts than stick cars. The Thump tensioner does in fact use the OEM spring. Look closely at a Thump on a stick GT car. You will see where the set screw for the stop leaves an impression on the arm from bottoming. Typically not an issue with automatics. All of the aftermarket billet tensioners address the bending/braking issues as they are stronger. But bottom out the tensioner and you will still loose the belt. To address these issue a stronger tensioner with more spring tension is required. Again stick cars really benefit from the additional tension on the belt between shifts.
I still bet that the OP has an alignment issue to resolve as well. If it's peeling a couple ribs off the belt. Tensioner is bottoming out, causing enough slack in the belt that it moves over. Tension returns with the belt moved over a couple millimeters and slices the belt.