P71 Road Trip Car–Freeing up the exhaust

The Crown Vic recently had its suspension massaged to the point that it is now a flat cornering machine in search of more horsepower.

Realizing that the upcoming road trip would be covering thousands of miles, and consequently, consuming quantities of hydrocarbon fuel, something should be done to maximize its fuel economy – oh yes, and give it a nice sound.

Once again we consulted Chris at ADTR.net, and he offered up a set of headers from Stainless Works along with a 2.5” exhaust system also from Stainless Works.  A few quick swipes of my credit card and both were on their way along with a set of Stage 8 locking header bolt kit from Ford Racing, and a set of Mr. Gasket Ultra-Seal exhaust gaskets, also from ADTR.net.  Then a trip to Auto Zone for four new O2 sensors.

In a couple of weeks the folks would crank out the headers and exhaust system, but there would be a hitch.  The ‘06 and later models of the P71 have the Watts linkage in the rear and Stainless Works has yet to make a complete system to fit my 2008 model.  I went to a local shop that does some of the nicest custom exhaust work on the east coast and consulted with them on my dilemma.  Not a problem, they said.  They had the 2.5” stainless steel tubing and would be willing and able to fabricate the rest of the system as well as include a set of Vibrant Ultra-Quiet resonators that I had purchased through Amazon.com.

There was one additional thing that I needed to have done.  The Stainless Works headers are a work of art and ADTR.net offered and option to have them ceramic thermal coated for an additional $400.  This is a very important option that is close to being a necessity.  In my trip to Indianapolis and last year’s IMIS I had a chance to stop by the Nitro Plate booth and talk with their sales & marketing manager, Cody Jones.  Now, I have to admit that I would rather talk to an engineer and technician that someone with Cody’s tittle, but Cody also knows much more than the typical sales rep about Nitro Plate’s products.  With the Stainless Works headers on their way I gave Cody a call.  He and I talked about what I wanted to accomplish and he let me know that Nitro Plate would be able to provide me with an excellent coating that would provide the kind of thermal properties that I was looking for far less than $300 – shipped.


When the box from Stainless works showed up I unpacked the headers and then packed them up and sent them to Nitro Plate.  Within ten days I had them back with their aluminum ceramic coating in a bright finish that withstands 1300 degrees F.  The coating was inside and out.  It looked fantastic.


With everything at hand I let RJ’s Custom Piping know that I was ready and they told me to show up in the morning.  Who could ask for more than that.

Soon the car was on the lift and the hood was open.


While I had a chance I looked over the stock two and a quarter inch system.  The exhaust manifolds were log-style castings leading into two sets of two catalytic converters.


Then travel along the driveshaft to an H-pipe and the dual mufflers.


Finally the bumps over the rear end and a straight shot to the turn-down tips.


The first thing was to cut off the tail pipes and then the bends over the rear were cut off.  These would be used as rough templates for the replacement stainless pipes.


Then the rest of the system was unbolted from the headers and set aside.


The headers were removed next.  But a lot of time was spent doing that.  The dip stick oil tube had to be removed, the steering joint had to be unhitched, and the engine mounts were unbolted at the bottom so that the motor could be jacked up for clearance.  Oh, yeah, before all that the battery was disconnected.

Each of the cast iron manifolds were unbolted and then the original exhaust manifold studs had to be removed since they would be replaced by the new Ford Racing bolts.


In the meantime work was begun on fabricating the new stainless steel pieces that would complete the system.


RJ’s has an amazing mandrel bending machine that can reproduce the most complex bends that you might wish for in tubing, including stainless steel.


Getting in the new headers was not too bad.  They actually pretty much slipped into place.  The only real challenges was ensuring that the EGR connector on the driver’s side of the car was threaded before the whole header was bolted in place.  The passenger side mounted quite easily except for a bit of a tight fit at the air conditioning pump and tubing.  The installer ended up taking off the serpentine belt and loosening the AC pump.



With both headers in place and bolts tightened it was time to put the system together starting with the high flow cats.  These things really flow, too.  Their diameter is huge and while they perform their intended function flawlessly, they do little to impede the exhaust flow.


The other pieces included the new O2 sensors, the piping to connect to the cats, and the x-pipe that continued on to the Stainless Works mufflers.  Now, again I had a choice of muffler styles and chose the chambered-type to keep the noise level from becoming obnoxious.


All the pieces were fitted together and clamped tight enough to get them aligned correctly before continuing with the fabrication of the tubing that went over the rear end and connect to the resonators.


RJ’s work is truly artistic.  As the pieces were fitted and aligned they were marked, taken down and then beautifully TIG welded together so that only one clamp was needed.  The clamp they used was a wide Easy Seal band clamp that completely conformed to the joint and ensured that they would never leak.



This was an all-day project and they needed it all.  By the time the sun was going down it was complete and I was excited to fire up the 4.6 V8 and see just how it sounded.

It was great.  A nice deep tone that converted to a free breathing sound when the car was wound up to 3000 rpm and beyond.

In the morning I checked the exhaust manifold bolts and was surprised that they were all pretty much tight.  I would be going through three or four heat cycles and checking their tightness before I would install the locks that would ensure they would never back out.

I had an opportunity for several car buddies to listen to the system and everyone felt that it was not in the least bit obnoxious.  It has a nice tone and yet breathes well.

Another surprise was the insulating properties of the Nitro Plate coating.  I drove twenty miles, stopped the car, immediately opened the hood and placed my ungloved hands directly on the headers without being burned.  They were warm, but definitely not hot.  It was amazing.  All that thermal containment had to be assisting the exhaust out of the system and releasing a good deal of power and efficiency.


This entry was posted in Automobiles, Car Stuff, Cars, Life and Cars, Modifying Cars, Road Trips and tagged , , , , . Bookmark the permalink.

9 Responses to P71 Road Trip Car–Freeing up the exhaust

  1. Kevin says:

    Absolutely amazing ! What a gorgeous exhaust job. I hope the tone is not overbearing though for a few thousand miles of road trip. How does it sound in the cabin at 70 ?

  2. Bring it to the 2013 One Lap of America! For the first time ever, we have a class just for the Panthers called “American Cruiser!” Come join the fun!

  3. Jim's sister says:

    As usual, your photos are great. Glad your getting closer and closer to take off!

  4. chris says:

    That is probably the nicest replacement system i have seen.Let us know if you get better fuel efficiency with the larger pipes.I have always thought the 2!/4 ” was too small.Thanx,

  5. Pingback: PRI–Performance Racing Industry 2013 | JIM'S GARAGE

  6. Pingback: PRI–Performance Racing Industry 2013 | JIM'S GARAGE

  7. Josh says:

    It must be nice to have all that money to throw at a $2000 car…

    • jimsgarage says:

      The CVPI only had 60,000 miles on it when I picked it up. It has evolved into a large sedan that rides and corners like a big BMW for a lot less. It gets more looks than a Ferrari and is the best road trip car I have ever used. Yes, it cost some money to get it there, but it is and owners choice.

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