You can also try to tap the area with a hammer to try to loosen the crust and crap that is holding the bolt in.

 

if you got a welder, a mig would work great. you could weld a nut onto the end of this bolt. then try to reef on it again after tapping the area with a hammer.

 

i had the same problem you talking about the bolt that goes through the alt off the bracket with the alt and smog mine was seized in the alt but wasnt seized at the threads only way was to cut it out lol if u can post a pic to see where the ball park is cause heating works but can also cause the bolt to snap and never use 12point on an old vehical 6 point point only that way u dont strip the head

 

what i ended up doing, was grabbing a 3 jaw pulley puller from autozone, because I needed one to get the timing chain and gears out anyways. I then proceeded to put my chain tool around the pulley of the smog pump and then undid the bolts there. then I got the 1/2 inch socket with the 2 foot breaker bar with a downsizer to 3/8ths drive and proceeded to break it like that. Worked like a charm. I got everything back together. But the damnest thing happened. I had to take off the thermostat housing to get one of the bolts in for the timing cover. Well the one by the bypass snapped off. I tried to drill it out. But that did not work. So I got very close, but not finished. MACHINE SHOP HERE I COME!!!