Intake manifold bolts

I'm searching for intake manifold bolts. Specifically the two studs on the outside of the intake where it attaches to the head. I'm swapping parts from an old head to a new head and have tried every method to get the studs out of the old head. They are hopelessly stuck. I've searched and searched and can't find new ones. Any help?

If you're dead set on removing them, slot them with a dremel or something so you can use a screwdriver. But, the easier thing IMO would be to just go buy some threaded rod and make your own studs. Just cut to length.