So the other day I got a 18" magnaflow Part number 12259. I decided to try installing it myself since stock muffler is bolted in. Install was pretty and the time could have probably been cut in half had I read something like this before I tried doing it. This is also my first time using photobucket so hopefully everything works. My truck is also a Outdoorsman so i have a single outlet exhaust. I don't see why this would be any different with a dual exhaust, you would just need two extensions and 1 more clamp. I looked under my fathers truck and this should also work or 3rd gens too.
To install the 18" you will need three 3" muffler clamps and one 18" 3 inch muffler extension. I picked up the parts at autozone. extension cost 8$ and clamps were 3$ a piece.
First you will need to cut about an inch off the extension to make it fit about perfect. I used a jig saw but hacksaw could be used.
The pipes with the 3" ID fit a little loose when connected to the 3" OD pieces. So I cut reliefs so the metal could bend when the clamps was tightened and hopefully seal off most of the exhaust. This is what I mean but reliefs, they also use this technique on stock muffler.
Both ends of the muffler are 3" ID pipe so they need the reliefs cut. I did 4 but would probably put 6 if I did it again, as they were bigger than the extension that was 3" ID. The comparison is shown below.
To take the stock muffler out you will need a 15mm socket. Undo stock clamps and hangers. Both the muffler and rear tailpipe with resonator are on hangers. I removed the rest of the tailpipe to get the muffler out. Removing the stock muffler requires a little finesse but is manageable. My truck only has 5000 miles and it wasn't easy might be a little harder for a truck with some miles.
Next I placed the extension on the tailpipe and hammered it on with a rubber hammer and clamped in placed. The next part was a little tricky because I dont have a lift and truck wasn't jacked up. But I put the muffler on and fot the tailpipe in placed. You will most likely have to move the muffler around to get the tailpipe in. This part along with getting it to line up was a pain but not very hard. Once everything is inplace clamps and your done.
Now for sound. I'm really like it but its not as loud as I was hoping for or imagined, especially since I started the truck when the whole exhaust was removed. Now that sounded good.
I do have a tt that weighs 7420lbs and will be pulling it next weekend. This is the reason I got the 18". I do not think it will be too loud infact I feel I hit the gas harder so I can hear exhaust. My father had a 97 with the 5.2 which had a thrush glass pack and that was much louder. I think it sounds good and is deep but think it could be louder. If you have kids or a wife that doesn't want to hear it the 18" is probably what you want. Havent made any trips of distance to hear drone. My wife even commented saying it could be louder but while driving I can ask her what cars is coming at us and she can tell me the manufacture along with the model, sometimes engine but not always. She likes cars and the exhaust so it was easy for me to do it. Hopefully this helps someone if they are planning on trying to install it themselves. I think if you bought the 14" all you would need is a 2ft extension and just cut down to size.