Super six

one thing I noticed when I gasket matched the exhaust outlets of the manifolds I have done.... when the gasket is set there and lined up with the bolts, the original exhaust hole has been not only smaller than the hole in the gasket but also off center within the casting, I have only had to grind out 3/4 of the way around the circumference of the exhaust dump, the remaining 1/4 of the way around, the existing hole for the dump already touched the edge of the gasket. and 180* from that spot, I have had to take out as much as 1/4" of material to agree with the diameter and location of the exhaust hole in the gasket..... dwindling down along the circumference both directions, from that thickest point of manifold wall, and I tapered the whole area back towards the heat riser deep into the manifold but I have never touched the inlet side (ports) of a /6 exhaust manifold yet.