Broken Bolt in Water Pump

I am getting tied up all day with preparation for two family get-togethers so it looks lie another night or two of soaking and back on it Monday early eve. BTW: This is the original pump and bolts on a 51K original 340 so I am going to attempt to get the pump off without damaging it. Of course, that is until I get really frustrated and then out comes the air chisel. ;)