The standard package that I use on heads I sell and the heads we prep for BBM "complete" is 75-76cc. Intake valve drop is .200 on a 2.200 intake valve and exhaust .270 on a 1.650 diameter. This works well with my valve job and the valves I had Ferrea make for us. The "drop" measurements may or may not be right depending on valve diameter, margin thickness, and top cuts on a valve job. This is where I settled in on my set-up, so take it with a grain of salt. CC-wise, at those depths, the volume will be close to that. I have milled the BBMs to low 60s with no issue, and even to 58cc on one pair, which was almost .110 milled off. No problem....they are THICK.