I do believe someone here has reported shaving enough to take all the flat area out of the chamber.....that would be in the .100" range, + or -. The remaining chamber size would be in the low 50's of cc's.
That's a lot of material. Don't forget the .090 off the intake surface. Might as well get a different pair of heads or use those open chamber heads with some zero deck flat tops. What would the compression be then?
