Has anyone had trouble with their plug wires popping off the spark plugs by themselves? I have a set of 9mm Ford Racing wires on my 351w that keep popping off while the engine is running. Usually, I just find one wire at a time that has come off. But, yesterday I was letting it warm up in the driveway and I raised the hood to find three wires had come loose. Could the heat from the headers make them pop off? Should I try crimping the plug wire ends so they clamp the plug a little better?