I heard back from Jegs and it looks like i need to contact Weiand with some measurements.
this was there reply,

We contacted Weiand and they told us the best thing to do
was have you call them at 1-270-781-9741.They can help you get the correct
part number on the pulley you are looking for.They are going to need some
dimensions off your supercharger

So it looks like i need to do a few measurements and give them a call.
cheers barnsey