I understand the confusion with the info on the Zelensis site, The car on the site is indeed a Carina and not an Zelensis. I have to make the update on the site but at the momment I have some troubles to do so.
The Ockelbo is build in the mid '50 by Erik Lundgrun and is not more than a copy from a Ferrari mondial 500 of his friend.
I d'ont know if he build only the body or also put them on chassis but apparentlly there was a wide range of chassis available like the Volvo, Austin healy and the VW.
The Carina is a later copy of the original Ockelbo and is today still available as a kit-car.
Here is an other Ockelbo on VW chassis.
Bart