I read the other post. You still have 1/2 of the head so all hope is not lost. add a little heat a few times. shoot it with some pen. oil after each heat session.. next is the small ball peen hammer and the punch or cold chisel. keep working it back and forth evenly. It is just a little tight from he corrosion. give it a chance to break free. patience mang,.... patience. R.B.