This was the DOD 14. Wicked easy install. I was done with it inside of 40min. No air tools. However it seems I still need to do some tinkering. My right side tailpipe won't tighten solid at the extension pipe clamp.

Took it for a cruise and it's really not as loud as I thought it would be. I was looking for something more than the stock sound but nothing outrageous. My first impression is this is exactly what I wanted. Glad I didn't go with the 18. I've got a 70 GTO with a 455 and 2.5 pipes off RA IV manifolds and FM's on it that is real loud so I know what loud is. I didn't want that on my every day driver.
I did feel a bit more vibration at some rpms coming through the floor. Can't report on any performance gains/losses although either way it's probably too minimal to tell w/o hooking it up to a dyno.

Gotta hit the highway on my way to work this afternoon so I'll get a good idea of noise at highway speeds.

More on that later.

 

My understanding is that with new mufflers it takes a few hundred miles for the muffler to "break-in" and after that period the exhaust note/tone will change a bit. That change usually results in a bit louder tone if I am understanding it correctly.

But, I may be wrong.

 

You're quite right about the break in period. After reading most of the reviews for the 14" I was just expecting it to be louder out of the box.

 

Glad I went with the 14, mine is in the mail.

 

Stupid question, but what exactly is Mufflex. I was on their website and I saw Magnaflow mufflers.

 

Mufflex just designs the kit to fit on the truck without cutting or welding anything (DIY). They use a magnaflow muffler.

 

Thanks, so it's something to consider since they use Magnaflow. Anyone know what piping they use? Stainless or Aluminized steel.

 

Supposed to be 409 St St. pipes.

OK, as for highway speeds I didn't feel the drone was all that bad crusin at 70. With the windows open it barely audible. On the way home with the windows closed it was still tolerable, IMO. It was louder if you were crusin with your foot into the pedal obviously than if you were at say half throttle.

I think the drone was more noticable crusin at abour 40-45 at 1700r's with the windows up.

So far I'm satisfied. Time will tell when the muffler breaks in as to how much louder it gets.

 

Installed mine last week.. Same results. Not as loud as I expected but awesome sound none the less.

 

BTW! I had the same problem with the pass. side tail pipe not tightening up. Slide the clamps all the way to the edge of the pipe and tighten it. If you don't slide it to the end it doesn't compress the muffler piping around the tail pipe. Hope this helps