I'm really peed orf!......lovely blue #4 has blown her head gasket AGAIN, exactly same place (adjacent to the righthand oil way to the camshaft).....the top of the barrel has been faced off and the threads helicoiled.....only thing not done.....head refaced....reason 2 bluddy big studs that are fixed into the head at front and back, and which defy all efforts to remove.....anyone had cause to remove these studs, and if so, how?