Well, if this is a custom manifold, why stick with the round T.B. opening? Personally, I would have went for a Cobra-style oval T.B. and opening, might have matched better to the intake.
Since this has never been done before, I applaud you for trying new avenues to make power. I guess what is really needed is to see the manifold in action and a comparrison to a stock oval port intake to determine any benefits.
