Does anyone have the inner diameter of the Series II stock rear exhaust manifold primary? Particularly right at the flange, if that'* the most restricted part?

(Better yet, a good estimate of what it would be if any ridges or welding flaws were ground out...not "ported", just smoothed...)

If, like the front manifold, it'* not perfectly circular, how about an "average" diameter?

Thanks

I just measured 1 5/8" at the flange and 1 3/16 inside the weld.