Thanks Dan! I already opened up the flanges! easy work and still plenty of meat for a good seal and strength. I went in a few inches to make a nice gradual transition to the flange so hopefully that smooths out the flow a bit....I will look into the reversion theory... I think that is more of a factor with cams that have higher overlap? I might email Andy and get his take on that! If it sounds like I have too much time on my hands I do! Lost my job as a Pilot so using this free time to finish my project.... TBF