Save the W2's

Looks to me like they just hit the end of the casting of your guides with an end mill bit. Your intake guide was casted thin on the one side in this picture... appears to be left alone and as casted around the blend area from guide to runner area. I'm not sure there is anything wrong with it..... You have the actual guide from that point up towards the top of the head to control valve geometry. "However, all the casting porosity looks awful"