I smoothed out the combustion chambers with some sandpaper rolls that came with my port/polish kit when I recently did my cylinder head. Then used a piece of plexiglass with a hole in it to cover the chambers and squirt in a metered amount of tranny fluid to see the cc volume of each chamber. That way I could sand off more metal where needed to even out the chambers. Then I used the scotch-brite cross buffs to polish them to a shine.

Sounds like you already have the head on so it may not be worth taking off but if you notice pinging after awhile and your timing seems to be in range, this might be something to consider.