Cliff, I use something like that , but sparingly. All the work on this head will probably be accomplished with sand paper type bits. Those carbide bits can grab a lot material if your not careful. I did use something like that for cleaning up my mikuni intake-bad castings. The "teeth" were clogged up with aluminum which was actually a good thing, so it wouldn' t gouge the project. I'm figuring I'm down to 38cc right now, but there is room to open up around the valve curtain. that should gain me back some. might wind up grinding reliefs in the pistons which will get me a little more. I am very happy the way it cleaned up. The only signs of rust are barely seen on the pivot bushings. I will be getting a burret set-up shortly. i've noticed if you stay away from the auto-performance vendors, you can order a pretty cheap set-up from a science lab web site. You can get a 50cc burret, stand, clamp for 50$ and go find a piece of plexiglass