I'm guessing there is very little to no benefit from ported cylinder heads with the draw through setup. As I get more in tune with completing two of my projects I am getting closer to being able to pick and choose from my parts hoard and let others benefit from the rest of it. I imagine the turbo mount flange to intake restriction cancels any benefit of head porting until boost pressure takes over. Then of course with draw through boost levels are low- on an 83 I had I was able to run 12psi on the right day but I would not consider that again. I don't remember anyone sharing their experience with cfm flow or other greatest hits with these draw through systems on forums before. Just interested in any thoughts.