Camsore, all those things ever do is stick. I solved that problem on my '36 Chevy pickup by making a stainless steel shaft and staniless steel bushings for the exhaust manifold. That was over 25 years ago and it has proven to be a permanent fix.
All that hammering, twisting and penetrating oil simply doesn't fix the problem permanently, and it makes a real mess while not working. I know because I tried before finally biting the bullet and making the stainless steel parts.
I'm told by an automotive engineer that unless you live in Ethiopia, an engine warms up much more quickly with a functional heat riser. That's why the factories all used them.
