CNC Mill Mark Removal in Intake Port

273 said
I know it's not a cnc head but came across the video thought some might be interested in the results.

14:50 is where he shows the flow chart, recap under .500" there's little/no change above to 1.00" 10-25 cfm gains with 60 grit.

That's a good example of how the valve job controls flow below 0.300-0.400 lift and the port doesn't matter all that much until velocity gets high. Those were big changes at high lift.