Det är som jag skrev och likadant med "portningen"
The Pinto engine was originally designed in the 'states as a 2.3 litre engine for the Ford 'Pinto' (essentially an American Capri) and the inlet ports reflect this capacity, in that they are already too large. Because of the sharp turn in the port and the angle of entry of the fuel/air mixture, the bottom third of the port carries virtually no flow (see diagram). It is wise to concentrate on the upper part of the port and the far side of the valve seat. As stated the port is already too large, so all that is required in the first part of the port leading to the valve guide boss is a cleanup of any bad casting marks and a smoothing of the bevel at the manifold face. For extreme head work, part of the bottom of the port is actually filled in