SBM Port Molds

I put up a similar post on Speed-talk. A gentleman there said this type of port is more about complete fuel burn than it is about air flow. He said the GM LS7 port is similar. Of the three options I listed, I thought the fuel shear ridge was the least likely. The ridge in these heads is not sharp, it is rounded/eased. I actually thought it was more about air flow than wet flow.