Ported X head 340 header size?

Thanks! I do see that the 1-5/8” flow enough. What always bothered me is the idea that exhaust flow out of a port with equivalent area to 1-7/8” is hitting the smaller header right off the exhaust port. That airflow “dam” off the port has to cause some turbulence that can’t be very helpful to flow.
When I built/modified these mid-length headers out of a full length set, I did try to radius the transition in the flange a bit, but still... :)