The 91 -94 Classic Saab 900 Non Turbo 2.1 Liter Motor came from the factory with A bum head gasket. The replacement head gasket lacks many of the coolant flow holes and the metal rings around the cylinder openings were made wider. On the old head gasket the coolant passages were made in to it and were not needed as the block side had the opening and the head didn't. That concludes that the manufactured openings in the head gasket were a weakness and not needed as coolant didn't flow through the block and head there anyway.
The Head Gasket on the 2.0 Liter "Turbo and Non Turbo" underwent the same design change.
Note the Erosion around the coolant passages. This is the effects of A Bad PH level "Old, Cheap and / or poor quality antifreeze" and high fluctuating engine temperature. We recommend Mercedes Antifreeze and the cooling system modifications as per the links to Cooling system service or what ever link brought you here.
Head Gasket Procedure
Cooling System Service
Blown 2.0 L Gasket
Latest Design Head Gasket