Exhaust tip inlet size

I know on a stock '69 Dart GTS they were 2 1/4". However, inside the front part of the tip it narrowed down to something under 2" for some reason. You can still get tips of that original (restrictive) design from places like Accurate. Or opt for 2 1/4" or 2 1/2" straight through. I think the OEM mufflers, or a copy of them, are more likely to give you the "correct" sound, not the tip design.