I have to remove my header pipe as it cracked and broke at the crook of the 'y' part where the two pipes coming from the exhaust manifold become one and go on back to the catalytic.

If anyone has a tip for getting the innermost nut off the exhaust manifold-to-header bolt connection I would be extremely grateful. I couldn't even fit a socket on the nut due to the proximity of the innermost pipe. All I could muster on it was the open end of a box-end wrench and I was not able to get the clearance or leverage to administer enough torque to loosen it.

I'm thinking it would be easiest to remove the entire exhaust train starting at the exhaust manifold and once down, remove this tough little nut at the manifold to header connection.