There’s the question of yield vs elastic stretch. You don’t want the belt to yield, but some people make the argument that you want the belt to elastically retard at higher rpms.

I’m in the camp of locking down the events and a belt with minimum yield or elastic stretch, personally.

 

I'm in the camp of a little elasticity and keeping less load on rotating components. I've used "non stretch" belts and after about 40k water pump bearings are shot. I"ve had to do one unscheduled adjustment on the belt and otherwise its been perfectly fine. I drive it to redline every time I drive it but I don't abuse it.

Certainly not intending t start an argument or indicate other options should be abandoned. Apologize for any hard feelings.