If the ports are cut after lapping, I use an fine grit undersize Flex-Hone in the bore to knock off any major burrs, which with sharp tooling should be very small. I don't power it. I just use it like a round file sliding it up and down the bore over the port area for a few strokes. Then I use my finish lap to touch up the bore. Only takes a couple of strokes and will change the bore size an unmeasurable amount.
Gail in NM