It sounds like you might have a Create-A-Breeze B8100 model fan, which is a Fantastic Vent series fan. The correct replacement for the fan and motor on 8000 series units is the Replacement Fan Motor Assembly Kit for Fan-Tastic Vent Roof Vent Fans # FVK8017-00 you were looking at.
If you can provide a photo of the spec sticker with your model number or the motor part number I can confirm this for you. view full answer...