Before you pull it off, you may want to take more time to try and pinpoint the area of the leak. I mean what if it's the piping that goes into the manifold.. at the rear where the brake booster hose attaches to a pipe and that pipe where it threads into the manifold. Spray some carb cleaner...
You'll need to take both the intake and exhaust manifold together and let them machine as one piece so everything is even. If you have them separated you should rebuild the heat riser area....at least new gaskets and check the insulator plate to see if it is cracked. READ the "intake and...