Very bad rasping noise when I accelerate !

I think the exhaust manifold gasket has gone ! the reason i think this is that i can see gasket, which seems to have risen up from the joint, and this could be as a result fo loosing manifold studs? does anyone have or know how many and where the studs/nuts should be, so i can feel around and see which ones are missing.
its an 83 gti cabriolet, 1.8k type injection.

oh and if this isnt what i think it is, please let me know the bad news. This was bound to happen, 2 weeks after I finally get everything working perfectly

many thanks
Jon

6 studs.