The manual for Okrasa exchange engines mention: "When delivered the Okrasa exchange engine type TSV-1300/30 and TSV-1300/34 are equipped with Champion L87Y and L85 spark plugs". The interesting thing is that the L85 is a normal plug-type for the VW engine, but the L87Y has an extended tip. When first reading it I found it a bit strange. Why do they mention two different types?
If you want to find the extended type in a specific brand look in the catalogue for Volvo 140 with B20 engine, they use the same. If you want to go one notch colder for your race engine, then plugs from Volvo 123GT will work fine.
The upside of buying the wrong parts was that I got a reason to change spark plugs in my Ghia. A long overdue activity.