So I've got a 69' mustang, not the boss or mach 1 though. Engine size is a V8 302 with dual exhaust. I'm looking to put in a set of x pipes with a pair of dump off valves on it so I can open and close the headers via a switch inside the car. The only thing I don't know is the actual diameter of the pipes. Now I'm guessing that they are the stock pipes, but I'm not quit sure. Is there some way that I can measure the diameter of the pipes without having to remove them or does someone know the diameter of the stock pipes on this year?