Can someone here tell me exactly when the Bendix Control Valves were changed to embossed letters? I have some here and some are 68s. But the raised letter I normally see on earlier mustangs around 67. Is that correct, every information is appreciated. And when exactly did ford changed the pressure port sizes. Was it really from 67 to 68 model so there are no 67s with the larger port? I just wonder if maybe then they changed the casting and started also with the embossed letters.