TTI Exhaust question

I had them on my 70 Dart, mild 360 with full length TTi system, including the Dynomax Super Turbo mufflers, not too loud in "normal" driving situations, but you will definitely hear it when you hammer the throttle. The 68 Dart that my brother recently purchased has a full 2.5 inch TTi system, sounds pretty much the same, in fact my brother is planning to put those mufflers on some of his other cars because he likes the sound of them