My truck (stock 216) came to me with the stock manifold and down pipe, but with a Cherry Bomb or similar glass pack right under my butt, and a side exit right in front of the LR tire. It's super quiet at idle and low RPM, but pretty loud in the cab at speeds over 40 or so. The floor is also rusty, there's no weatherstrip, no headliner or roof insulation, no floor insulation, no cardboard door panels... I almost always have the windows down unless it's too cold or raining. So there's lots of wind noise and the inside sounds like an empty soup can, so I know the volume isn't solely due to the muffler and tailpipe configuration.
No real point to all this, besides sharing what I've got going on.
I have a set of heated Fentons and Porter mufflers I intend to run. Just need to tweak the throttle linkage to clear the rear header, and get it to a shop to get some pipes bent and welded. I plan to have the mufflers back under the front part of the bed. I also have new floor panels that need to be installed, and when that's being done I want to ensure the cab is square, mounts are good, and the doors hang right, then I'll put some weatherstrip and floor insulation in it. Jon, I saw your note above and the other recent thread about the deteriorating cab mounts and cab to frame contact transmitting noise. I need to check and remedy that if needed. I'm tired of how overstimulating it is to drive for longer distances due to the noise and heat. Looking forward to it being a little more civilized while also having a good exhaust note.