UK Car Repair: removing intake manifold during head removal, mg midget, spitfire 1500

Question
i have a 1975 mg midget, with a spitfire 1500 engine. i have removed the carb, the exhaust manifod is loose, the thermostat housing is off. the studs have been removed from the block. the nut (badly rusted/size unknown) still connects the intake to the exhaust. the head is free on the block. having said all that the intake is slightly loose across the top of the manifold.  what is holding the intake to the head? shouldn't the intake come back from the engine with the exhaust?  where do i look?
looking foreword to your response.

thanks in advance
jim moore
kent. ohio usa  

Answer
Hello, the nut that is frozen on is presumably attached to a stud, which, i'm assuming, is out of the head? The unit is welded together by rust, the best you can do is to soak it with Wd40 and let is soak through,  If you se too much force you will break the manifold.