Looks like the afr eliminator head and the "wing flow" design they use on cnc competition port jobs. Its my understanding this is not a true swirl design but a much milder "in between deal",they also say its not just a flow improvement on the bench but was a dyno tested improvement in hp as well. In my opinion Afr is a reputable company and their heads definitely make power but I would be really interested to know if someone had any back to back dyno results in regard to removal of it on the afr heads as they never used to have it and now they do. Its interesting to see what theories come and go and the ones that get revisited and tweaked upon,much like the whole quench thing lol.