Broken front stud holding intake on. Rusty. Help

Not really sure what you mean. Do you have any pics?

Broken flush, so meaning you can't get a pipe wrench on it or anything?

Few different options. If it were me with my limited tooling i'd soak it for a bit with penetrating oil. If you have access to a torch heat it up also, let it cool. Then i'd hit it with some left hand drills and hopefully the stud will come out.