i would go back and cut that sharp edge off the dividers. This is probably not what you want. You need air to easily run back and fourth from runner to runner. There are pulses caused by valve opening and closure events as well as piston speed changes that change the speed of air needed to go by the valve. It would be different if 2&4, 6&8, 1&3, 5&7's valves opened together as the air would travel from the plenum to both runners together making a sharp divider necessary. It just does not work that way. The pulses in the intake manifold follow the firing order of your engine. 5&7 are 90 degrees apart this is as close as it gets. More air flow can be acheived if you have nothing that causes spikes in the airflow.
Not claiming to be an intake manifold guru but, this is something you do not want to do.
Leon