The outside meaning the topside? There are no cracks on the top side of the block where the tube inserts if I am understanding you correctly. Not sure I am though. If you mean the underside, opposite the crack it seems to be ok.
Yes, the outside. How far up to the outside of the hole does the crack come? I agree 100% thet you NEED to break that piece OFF and file the edges down. That in itself will stop the crack because the piece will break off AT the crack's end. Once broken off and filed, the crack will be fixed. As long as there is still enough length to the hole and the tube will still press in, it will be fine. Besides, doesn't the tube have a bracket on it that attaches to the head? If not, PUT one on it.
