I see Cuda tailpipe extensions in pipe sizes 2, 2.25 and 2.5. What was the factory size extension inlet? I am putting my wish list together for my 1970 v code Cuda and am going to run headers but have not decided on h pipe or x pipe design nor on the mufflers. I see a number of members are not fans of Flowmaster as I was looking at 40 series Flowmasters for this car. Any suggestions are welcome and thanks.