Size Variance in Exhaust Ports?

Is there any (good) reason for having the inner two exhaust ports on each head slightly narrower than the outer two? No variance in height, just in width, and the 4 "inside" ports are almost exactly the same size, and the 4 "outside" ports are almost exactly the same size.
Any thoughts?

Is there any (good) reason for having the inner two exhaust ports on each head slightly narrower than the outer two? No variance in height, just in width, and the 4 "inside" ports are almost exactly the same size, and the 4 "outside" ports are almost exactly the same size.
Any thoughts?


