I would upload some photos but it’s just too painful on a phone now. They reckon that use sealant where at the ends where the gasket and block meet, and to use sealant at the ends instead of the cork gasket. Plus gasket sealant under the gasket itself. Also you can use of cuts of spark plug lead to locate the gasket while you fit it ( in the mounting holes).
Others may have more experience and ideas though.