The rough finish is typically beneficial on the intake ports, as you said earlier, to help atomize the fuel molecules more uniformly. This seems to be less critical on the exhaust ports floors and walls, and probably wouldn't fall into a category of being wrong or right if your were to do it. Gasket matching is often overlooked as being helpful, but it is always a good idea to do on intake and exhaust port entry and exits....



Class III CNC Machinist/Programmer