Toyota Repair: exhaust manifold gasket removal

Question
Hi I have a 1992 Corolla with 120,000 miles. The car has an exhaust leak at the exhaust manifold gasket on both ends. The center 3 nuts/studs can be tightened but both end bolts did not seem to tighten so I am guessing the exhaust gasket needs to be replaced. Both end bolts look rusted & I am concerned they may break when I try to remove them. From your experience, do the end bolts usually come out easily or should I expect them to break off? Is there a good way or ways to prevent the bolts from breaking off? I have sprayed the bolts with penetrating oil, but since the manifold is pretty thick I don't know if the penetrating oil will go past the manifold into the head.
I appreciate any tips / help with this.
Bob

Answer
Hello, the bolts are steel and the head is aluminum, bad combination, rust and corrosion can be an issue, Arent the end bolts actually studs with nuts, the studs would just stay in the head, you can also try to heat them up with a propane torch to loosen them up.