I have a 67 Mustang Coupe. Rebuilt 302 (from 68 model).
I've had problems with rough running with my new engine. The problems are similar to problems I had with me last engine. I think it is a vacuum leak, but I cannot find one anywhere. I have replaced my gas tank because I saw some (minor) rust in there. replaced my fuel pump and pump to carb line. Replaced all rubber sections of main line. Replaced entire ignition system, and went to electronic (Pertronix) ignition. Have a new PonyCarbs Autolite
2100 which should be solid. The only things on this car which are from the previous installation are the intak manifold, the exhaust pipes (which are soon to be replaced), and the main fuel line (pump to tank) which has been blown out with compressed air.If not a vacuum leak, then does anybody think there could be a problem with the fact that the 68 302 fuel pump has a 3/8" inlet for the main line, but the main line on a 67 is 5/16"?? Should not be a problem, right? I just have a 3/8" fuel hose clamped down tight on the 5/16 line, and that's ok, right?