Rear Exit Headers---"NOT STREET LEGAL!"---?


Voda

Active member
Aug 26, 2014
41
Seattle
Have GT I'm pursuing. The paperwork has a receipt for installation of Rear Exit Headers (I would upload pic, but not sure how to) M-9430-GTX and it says in bold on the invoice from Ford "OFF-ROAD ONLY! NOT STREET LEGAL!" (exclamation marks and all)

Anyways, are these just way loud? Unbearable for trips, etc.? Input appreciated
 

Beez

GT Owner
Mark II Lifetime
Oct 28, 2016
194
South Denver
Any product for any car that removes or replaces stock cats, exhaust parts upstream from stock cats, O2 sensors etc, is not street-legal anywhere in the USA, for emissions reasons. I don't know exactly how long this has been the case, but I'd guess 40 years or so.
 

twobjshelbys

GT Owner
Jul 26, 2010
5,224
Las Vegas, NV
Ford had the "not street legal" disclaimer on the Ford Racing muffler (catback). It left emissions intact but MIGHT have been to loud for some jurisdictions. So the exhaust that gutted the emissions and replaced the headers back did in fact make the car not emissions compliant is some states (now many, since many have adopted CA emissions testing methods, which is as far as most of CA's stuff, perfectly reasonable). When I first registered and emission tested my car in Colorado (which used only tailpipe and visual check for cat/o2) they were surprised to see the GT and the tech had to get the site supervisor. He went away for about 15 minutes and came back and asked if I had the "whatever part number" exhaust that replaced the cats with the visual bumps (they knew, probably during the 15 minute "homework" through notes from other stations). Saying "no" they did the sniffer and everything was OK.

What is legal in your jurisdiction may vary. If you don't have any kind of emissions you probably don't have any worries. If you have a state that has emissions and confirms cat and o2 sensor presence and uses OBDII system readiness you probably won't pass emissions. The key is to be sure any car you might buy is emissions compliant (factory configuration, or the tune is compliant). For the seller, be sure to keep all the original parts so that it can be restored to emissions compliance. Get a PPI by someone that knows the difference!!!

(I got caught by this - the pulley / tune I had was not OBDII compliant and I ended up returning to factory to get CA/NV (and other) emissions compliance. )
 
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Gary

GT Owner
May 11, 2006
356
Festus, Missouri
Light throttle bearable. put your foot in it, very loud.
 

Beez

GT Owner
Mark II Lifetime
Oct 28, 2016
194
South Denver
The details Tony describes above about different states and jurisdictions having different emissions compliance standards is correct in a "for practical purposes" way, but I want to add a clarification that many of us performance enthusiasts are unaware of.

Performance modifications to cats and pre-cats exhaust and emissions related equipment on street-driven cars are all illegal under federal law in all 50 states. However those federal laws are widely unenforced. It then falls to the state and local jurisdictions to decide what sort of emissions compliance they will actually enforce.
 

gtjoey

Keep Smiling - GT Owner
Mark IV Lifetime
Oct 14, 2005
3,376
Voda……….The first complete off road exhaust set was created and tested By Denis Breitenbach and team at Roush.
DBK and I were there when they were testing it on the yellow car at the time.
There is actual data out there that the COMPLETE set up, headers and all with NO CATS actually LOST horsepower.
Its so loud its viscious, you can break your neighbors windows.
Also watch the starter wire IT can melt if not sleeved and moved over.
Most states its not legal and to me IMHO its not fun.
IMHO, I Loved the stock exhaust with the HEFFNER PIPE.
This way you pass emissions , have the sound and no other worries....
Ive done 25,000 miles on the Heffner on SEMPRE, It transforms the car but even that is loud.
A GOOD LOUD! :)
GTJOEY1314
p.s. someone go to you tube and look up the silver gt at Carlisle dyno run....it had the complete off road, pure orgasm but loud!
FORD GT DYNO RUN AT FORD CARLISLE...….Fred was 350 pounds and gtjoey had black hair!
THE VIDEO IS 7 minutes 37 SECOND...I don't know how to post it, pure orgasm baby!
 
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Voda

Active member
Aug 26, 2014
41
Seattle
Thank you for the feedback. Thinking this is probably louder than I want on the GT. This is going to be a driver for me and the wife for some trips over the mountains, etc. Need to be able to have conversation, etc. Have other loud cars that are fun for a quick jaunt, but after that, it gets kind of old...
 

gtjoey

Keep Smiling - GT Owner
Mark IV Lifetime
Oct 14, 2005
3,376
Yes if your bonding and conversation,thats not the way to go. Stock is best but to quiet for some.....
 

Beez

GT Owner
Mark II Lifetime
Oct 28, 2016
194
South Denver
Don't forget Ford Performance/Borla Racing muffler as the sweet spot for more growl than stock, but still easy to converse and not annoy the neighbors 🙂
 

nota4re

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 15, 2006
3,652
Back in 2006/2007 timeframe, the Ford Racing Rear Exit Headers - was one of the only exhaust available and I purchased and installed on my GT. I was the hero at any car show - easily the loudest car in attendance. At first I though it was kinda cool but after several months (slow learner here), it was just too loud. I removed and sold that exhaust to another owner - who heard it and just had to have it, go figure.

I'd recommend changing back to stock manifolds, stock cats, and a Heffner. That combo looks great, sounds great, and will be 50-state legal. I believe the OEM manifolds are still priced within reason but I imagine the cats are going to be expensive.
 

GKW05GT

GT Owner
Mark II Lifetime
May 28, 2011
2,515
Fayetteville, Ga.
2nd on Heffner exhaust as it will pass emissions looks awesome and is more than loud enough
 

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AJB

GT
Mark II Lifetime
Le Mans 2010 Supporter
Jun 28, 2006
2,723
Bloomfield Hills, Michigan
another option that does both... is the GTGUYS "X" PIPE .
It keeps cats but eliminates the large muffler can.. (either stock can or Ford Racing can)
I have listened to all three. I have had the stock and the Ford Racing On my car.
but I wanted to liven it up a bit !!!! so,
Rich just converted my vehicle to the polished GTGUY X Pipe last week and I should have it back
in my garage in a few days. !!!!!!!
andy (ajb)
 

HighHP

GT Owner
Jun 3, 2019
157
Ed Groce, Spokane, WA
I second nota4re on the Heffner. I live in eastern WA, without an opportunity to hear operating options. Kendall at Cooltech correctly guided me to the Heffner. I purchased it from him and installed it. PERFECT sound. Plenty of awesome music over 3500 RPM, something magical happens at that RPM. Normal driving very quite still in the cabin. Idle is very throaty, sounds like a borla. Also wrapped it to keep the heat down in the engine compartment. Maybe that helps reduce in cabin noise?
 

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PILOTJPW1

GT Owner
Mark IV Lifetime
Sep 22, 2005
860
Maryland
I like mine. 7000 miles of them. There not that loud in Normal driving. At least to me in the car.

don’t try and stand behind it and have someone stomp on it!
 
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2112

Blue/white 06'
Mark II Lifetime
I like mine. 7000 miles of them. There not that loud in Normal driving. At least to me in the car.
My experience as well .
.
 

SAcobra427

GT Owner
Nov 15, 2010
33
Pa
I've had the long tube headers and just a GT Guys X pipe on mine since 2012 and yes its loud. Put around 7,000 miles on it with this setup. Not awful inside the car if the windows are up, all the sound is in the back of you, its much, much worse if you are the guy behind it though. 🎧
 
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Tomcat

GT Owner
May 23, 2013
903
North Carolina & Perdido Key
IMHO, I Loved the stock exhaust with the HEFFNER PIPE.
This way you pass emissions , have the sound and no other worries....
I will parrot Joey...I have the exact same set-up (after listening to just about every exhaust/pipeoption at Ford Nationals-Carlisle 5 years ago) and have the same opinion. PERFECT for what I do, 42,000 miles
 

Bill Briley

GT Owner
Aug 9, 2005
212
Valley Forge PA.
I found -a modern well tuned motor , like the GT, will pass "sniffed" emissions without Cats.
True - it will flunk a Visual inspection- if the Mechanic knows where to look on a GT.
 

gtjoey

Keep Smiling - GT Owner
Mark IV Lifetime
Oct 14, 2005
3,376
Bill , It depends the state......
We need one out of two emission cycles to pass.
But in New York we are not on rollers BUT it has to run an evap loop and cycle. If it doesn't it wont pass.
Some states are safety only. Some states bypass the loop.
In New York it wont pass.
gtjoey1314
 

JoeZ

GT Owner
Sep 10, 2014
17
I agree. Heffner exhaust is perfect. I run this on my yellow car. It sounds sick and build quality is amazing!!