I just decided to keep it simple and keep things straight. The curvature of the pipes I was looking at is so slight that I didn't think it was going to be worth while. I might still be able to hit the 3rd harmonic wave so might be fine. It is also a full inch longer then the previous manifold. I really don't see this manifold having a hard time killing my old one on both the flow bench and the dyno. Also to keep things simple I might not even be tapering this plenum. Still haven't fully decided yet.