EGR holes on 318 heads

The bulk of the high velocity gasses travel along the roof of the port, so flow gains will mostly result from improving this area. The AIR (not EGR) ports were placed in an area of the port where there is little gas movement, making it easier to inject air under low pressure. When porting the heads, any bumps around the port should be blended flush, but beyond that don't sweat it too much. Focus on the massive step in the port roof, and the guide boss which are a far bigger impediment to flow.