Been covered a hundred times here. Soak in sili kroil, pb blaster, etc. and let sit for a day or two, then soak again and let sit for a day or two. After that, soak again and let sit for a day or two. Then use your easy outs or, if you have any bolt protruding from the head you can try to weld a nut to the top, apply some heat and try to back them out.
If all else fails, give the search a try.
John
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