The 4.6L are but the N/A 5.4L 2V haven't hit 300 RWHP yet. There is lots that have tried... The correction I made is correct... Ported 3V heads flow more than these new TF heads ported do. 4.6L 3V engines with ported 3V heads make considerably more power than equal 5.4 3V engines with ported 3V heads. If the 5.4L 3V guys cannot catch up to to the 4.6L 3V guys with better heads, explain to me how a weaker performing head is going to change that? I am tired of arguing this and proving it. I am going to put it to you quite bluntly to those that want to believe that a 5.4 will make more power than a 4.6L N/A with ANY 2V or 3V head, you are retarded.