header removal

this is my first experience with headers. I am taking them off to take my 273 out. They have stainless 12 point bolts holding them on. I got all but 3 of them out so far. Cylinders 1,2,8 still have one on that i cant get too. The tube of the header interferes with getting a socket onto it. I tried vise grips, but didn't have any luck. I'm sure someone can give me the answer!

Thanks,
Steve

p.s.
any other tips for pulling the engine would be appreciated too, such as do i need to take my starter off?