Damn Header Bolts!!!

You are talking about the passenger side bolt on the manifold arent you. Yes been there, done that. Broke 3 universals and 1 socket. That thing was a bitch. I said **** it, used high quality parts and it cam right off with some PB blaster.

The one on the passenger side right??? Yeah, its not easy to get to. Swivels and long extensions are the only way to get that one out. Spray some rust penetrating lubricant on there and let it soak in, then try again. If I remember right I ended up with a short socket connected to a swivel and then two loooong extensions that cleared the bottom of the car. That way I could use a 1/2" ratchet which made short work of it.

Good luck!