I have a 1971 c20 350 th350 trans with a magnaflow exhaust. The engine and tranny are stock. My throttle response is a little late. Sometimes when I idle at a stoplight it will start to shake and when I drive it bogs and cuts out and almost dies. Also when I'm on the highway I can get up to 65-70 without cutting out. The other day I went 80-85 with out a problem and didn't change anything. I've changed my inline fuel filter and the carb fuel filter. I think it has bad acceleration also. It won't even spin the tires when warmed up when I put the pedal to the metal. Thanks for reading. Any help is appreciated.