I have a 93 f-150 with 5.0. The exhaust is a single 3" with no cats and a 3"IN/Out single-chamber flowmaster. Its dumped right under the cab. It sounds great...very deep and plenty of volume, but lately, Im just wanting a little bit more quiet inside the cab. lol.

So what Im wondering is, will moving the muffler a couple of feet back lower interior sound? Also, I wanna keep it turn-downed....cuz that way it just shakes everything, lol Thanks guys.

 

Yup...if you move the muffler under the bed (just before the rear axle), then the interior resonance will decrease significantly.

 

or maybe add a resonator?

Mike

 

I'd add a resonator, but I just LOVE the rumble it has right now.

I will move it back near the axle first...hopefully, that way, I can have a conversation inside the cab without yelling .

 

Wait... Before you do that, just cut that turn-down off, and get a piece of pipe bent in a 90, and bring it out so it exits the side of the truck. (preferably in front of the wheel)
The drone sound is from exhaust pulses reflecting back up from the road (you will notice that goes away when driving in mud or snow) and resonating through the floor. It has nothing to do with your muffler position, but where the exhaust exits.
A proper muffler install will not allow sound to come from the muffler at all (no leaks), unless, of course, there is no pipe after the muffler! haha

I learned this from years of playing with my own exhaust systems on my various Fords. I have done a lot of home built systems, and all without a welder; only clamps, hacksaw (I graduated to reciprocating saw a few years back, lol!).

Mandrel bend kits are now available for do-it-yourselfers, which I think is a great idea. Comes with assorted bends, lengths, and optional axle bends as well. Ends are flared so they fit together nicely. I also used exhaust cement paste to seal connections when I slipped them together for final assembly and clamp.
Mark