Head Porting on Exhaust Runners
A gasket match is to match up the outlet of the port to the inlet of the manifold or header. If your trying to gasket match the head to anything but an exhaust manifold, your not going to help anything. Most headers are just round tubes that are no where near the same demensions as the exhaust port.
However, if you know what your doing...some bowl work, and blending the valve guide boss can improve flow quite a bit. But getting into the short side radius and taking too much off in certain areas of the port can quickly ruin a set of heads.







