Confused about blower pulley size

I am confused about the stock size of the Lightning blower pulley. On here it claims it is 2.93" but my blower pulley is nearly 4" in outside diameter and measures 11.31" around the groves, which means a diameter of 3.6".

This all came about as I installed another supercharger off a 2002 HD onto my truck so I could send my stock supercharger off for rebuild and porting. The HD supercharger has an Metco mandrill and a pulley that is 3" in outside diameter and 8.625" around the groves, which means a diameter of 2.74". (and I think my stock belt may be slipping with this smaller pulley).

Someone please explain for me?

Thanks

Walt

Lightning stock - 2.93
HD stock - 3.1
that 2.7" pulley is aftermarket

IF you have a pulley that is a 3.6, its off a cobra.

Dusten, thank you!

I think when I had my 01 lightning tuned for towing, the tuner put that 3.6" Cobra pulley on the blower to lower the boost and make it safer for towing. It made 323HP and 363 ft-lbs with max boost of 8.2# and it was tuned for 91 octane. I used it for towing many times and no issues.

These trucks make 8lbs stock and will dyno at 350whp. That's an odd combo you got.