69 Dart/Barracuda 340/383 tail pipe size?

VOETOM said

The pipes are 2.25" OD as they fit inside the mufflers. :). But the tips have to fit inside them so hence the reduction. And, clearance for springs and frame was important so they used the flats and smaller pipes.

Click to expand...

Yes and had to make sure cars could be thrown together quickly on the assembly line and not have pipes hitting frame, gas tank, leaf springs etc. So the small pipes with pinches restrict flow to some extent but were ideal for a production car assembly line purposes.