[slikside]

Originally Posted by 67CC

Had the same problem. Tried PB Blaster, Kroil, the freezing stuff, fancy tools for getting off rounded bolt heads, without success. Think there was two of them too. Don't feel bad. Someone once said exhaust manifold bolts are the hardest job on a car. I believe it. Took me three weeks.
There are only six. You need heat. Forget map gas. Oxy-acetylene until they are bright orange. Then I was able to get them out with a vice grips. Focus heat on the manifold only, not the head.

This. heat is your best friend in these situations. Like he says focus the heat on the manifold where it surrounds the bolts. that is the metal you want to expand.

I'm guessing that's why these bolts are rounded...someone tried a little too hard without heat...and they rounded.

Oh, and one more thing. Don't be afraid to tap on those bolts with a hammer after/during heating. The shock will loosen things up too. Just don't miss and damage your manifold.