head porting question

Art, that area is best left to a machine shop with deep reaching tools. Those valleys on each side of the guide is something you really need a long shaft bit and they do not come in a small dremel size. Just a larger size that you would find on a die grinder.

What some shops do is ethier whittle away until thedesired shape is found or they have the head in a stand/jig held down under a drill press. A bit is in the drill of the press and moved downwards cutting away the top of the guide and the boss around it until the desired height is achieved and then the die grinder is used to finish it off.

Shop work. Not many can do this at home. It can also be dangerous at home if things are not set up right. It aint preety seeing a heavy iron head flung across the garage floor.