exhaust gaskets

I got a little maintenance package today. I was able to get the manifold gasket on but I wanted to replace the gasket for the riser. Is there a trick to getting the riser and manifold separated?

More than likely the bolts will snap off. There are two that are around 4 1/2" long and two that are around 2 3/4" long.(cant remember exactly how long) The long ones almost always snap.
I was able to get some of them out by heating the outside of the riser with a torch(a real one not propane)and working them back and forth till they came out.
The ones that snapped, I was able to get a pair a good vise grips on and with more heat and Pb-blaster worked them back and forth till they came out they came out.
Re-tap the threads to clean them up and I used anti-seize on the new ones. I also take them out and apply new anti-seize every fall and have no problems with them rusting now.