Questions about torq storm

Yes I have it. I will get you measurements tonight after work. I think it was 9&1/8". I still haven't figured out if I'm going to buy the 10 rib belt tensioner which is 435 bucks!

OR get the whole damn 10 rib kit which is around 800 bucks and it uses the double sided belt tensioner system which I like better...?

https://www.holley.com/products/superchargers/supercharger_components/parts/91201