Yeah, I did the Kroil thing, no luck this time.
Before drilling I even tried the old welder's trick of welding a nut on the broken end of the bolt. Done that many dozens of times and, till now have had a 100% success rate even on exhaust of other vehicles. Not any more. It only worked on 1 of the 5 little buggers.
Drilling is always a last resort for me.
To add insult to injury the friggin' easy out broke off in one of the bolts. Ooh, I cussed just a little then.
Had to use the hot wrench very carefully on that. Luckily most of it came out and as I was just hitting the end of the bolt remains with the left handed drill it caught and backed the stub right out.
On the rearmost bolt in the head I ended up drilling a little crooked, since the firewall was in the way, and ended up tapping the hole and enlarging the hole in the manifold so the off center bolt had some wiggle room.
Tell you what stuff like this makes me realize I'm getting older. 30 years ago this task would have resulted in thrown tools, smashed body panels and lots of yelling copious amounts of swear words. This time I think I only swore twice when the easy out broke.