1970 Duster project in Sweden

Flat surface plate and sandpaper to make sure housing is flat. Use a paper type gasket, and permatex "indian head" gasket shellac. It wont leak.
Thanks. I did the sandpaper and flat surface today, paper gasket and regular rtv was what I had. I think that one of the bolts bottomed out (stupid mistake on my behalf). But that is now fixed. Will let it cure overnight.