Cuda tailpipe extensions

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.

One question is are you going to drive it on the highway for any extended periods of time and if you are do you want to hear the stereo and be able to talk to anybody that might be with you?

Yes, i would like to talk and hear the radio. Probably the longest highway drive will be an hour or so.

The factory inlet I think is 2.5 with a 2.25 outlet but what does it matter since you are not running a stock exhausted any way. Plus the tailpipe and the muffler are a one piece unit in stock exhaust.

Ok, I have headers and the Accurate H system with 21/2 in and 21/4 out all the way back with their quietest muffler and resonators with tips. They have better flowing mufflers that look stock, but after driving an hour, I wouldn't want it any louder.

Factory tips are 2" on all cudas.