Fox T-Bird/Cougar Forums

I am currently running a stock 5.0 engine with the Y pipe (cat hollowed out) and a pair of IMCO 72443's (clones of Flowmaster 42443's) with dumps before the rear axle. I am getting a nice sound but it's still not what I was hoping for.

Is the problem the sound of the lers I chose ? Or will better headers like Hedman's 88380's and an off road 2.5" h pipe change the sound of the exhaust at all ? If I change the headers will that require other mods ?
I also do not know which headers will fit better...shorties or long tube ?

Any help or info would be much appreciated. This is a project I plan to take on in the spring time, but im just trying to get as much info and recommendations as I can.

Thanks :roxor:

Any kind of headers will require an H-pipe.  The pipe is too small on the y and the s have a way wrong stud spacing.  The H-pipe will also require mid pipes to fit the s at the back and feed into the lers.  I know from experience that if you have 2" ler inlets still, stock Mark VII mid pipes (and you'll have to buy s, too) will be exactly the right length AND will seal against the ball  on the back of a 2.5" H-pipe.  If you have large inlets, get Mustang mids and use some straight tubing to make them long enough to reach the lers. 
And get rid of the dumps, man.  They're unsafe, ESPECIALLY with hollow/no cats.  At rest, all that uncatalyzed exhaust is pooling under your car.  A submarine with a screen door is still sealed against air leaks better than an 80's car, even ours.  You don't want that  getting inside the car where you have to breathe it.  Just sayin', your health and stuff.

So this H Pipe will directly fit the Tbird, or will I need any extenders ? http://www.summitracing.com/parts/cto-4179

What about the lers ? I would think the 44';s would sound great, but these are clones. I was told by several people that they are the same design.
The Tbird has 2" pipes, and I am wondering if that is too restrictive.

That H-pipe will fit directly, but you will still need pipes and s to reach the lers (Walker 31885 s, 42852 and 42853 mid pipes).  At your level, 2" dual cat-back is just fine.  I'm running a 2.5" H with a 2" dual cat-back with dynomax super turbo's all behind an HO cammed Explorer engine, and I almost break into the 13's.  I think I'm maxing out my 19# injectors.  But you're not possibly going to restrict a stock 5.0 with stock E6 heads and a 50mm TB by running 2" duals behind a 2.5" H.  You will, however, need to slightly adjust the lower bracket of your column shift to clear the H-pipe, and you'll need extenders for your oxygen sensors (or just a pair of new ones for a Mark VII or Mustang).  Since the headers won't have a place for them, they'll have to be moved to the H-pipe, without extenders (at minimum) they won't reach.

My Y pipe has no cat, or it's hollowed out. Isnt that the same concept as having an X pipe ? Im thinking maybe of just getting a pair of Walker tails to exit out the back. Not sure if im crazy about the turndowns at the rear axle.
It sounds like too much work to add new headers and an h pipe. Im not looking to race anyone, just want a better exhaust tone.

What is the difference between the stock 5.0 headers, and say, a pair of Hedmans or BBK ?

Knocking the substrate out of the y-pipe won't improve flow, as that's not the restriction in that particular unit.  And an X-pipe is a completely different concept.  The X-pipe uses expansion waves to aid cylinder scavenging similar to an H-pipe, but with a different profile.  As for the question of difference, stock you don't have headers, you have cast manifolds.  They're small, heavy, and restrictive (more so than the E6 heads), where actual headers are light, have large outlets and are made of tubing bent in such a way as to protect maximum flow.  If you're just looking for a sound, it would help to know what you're looking for in a sound.

I have noticed improved power and sound since I hollowed out the cat, and added the K&N air filter. Im just looking for a more aggressive rumble or growl to the exhaust.

If I change the headers, what else needs to be changed besides the pipes ?

If you are looking for a set of stock mustang headers, I've a set I'd sell ya to further your cause..

With a stock cam, you won't get much more than slightly increased volume with headers only. It takes a cam with some added lift, duration, and overlap to get the lope sound that some people get such a hard on for. I've also seen many 14 second cars that sounded mean as hell with a mucho choppy exhaust note, but were slower than a 10 year old stock Honda Civic.

Myself, I'd rather spend money on go fast rather than sound good. With quality exhaust parts however, you'll get a good exhaust tone. I like mine mellow, and throaty, not where it sounds like rotten glasspacks with big holes rusted in 'em.. ;)

If you add headers, you'll need an H-pipe, which will cause you to need extended oxygen sensors.  To get from the H-pipe to the lers, you need mid pipes and s.  That's the whole upgrade path.  Everything except the lers.  Make sure you use header gaskets from the company that made the headers.  I found that out the hard way with my BBK's.

You're not going to get the "growl" with a single exhaust. (y-pipe in => single => y-pipe out is still single exhaust, just with lots of useless weight like an extra ler and tail added and no extra flow).  Maybe you could just shoot for loud.  Loud is aggressive.

This isn't entirely true. yes, it would help with flow, but it isn't a necessity. My old 88 Sport had stock mustang headers and the stock t-bird y-pipe when I bought it. the holes in the s on the y-pipe had been slotted slightly, but it does work and will seal just fine. ALTHOUGH, you WILL have to have o2 sensor bungs welded into the y-pipe, which makes it almost pointless to keep the y-pipe. I did upgrade to a 2.5" h-pipe when I came across a smokin deal on one, but what it had worked...

So is my 5.0 EFI enigine the same as the stock '88 Mustang engine, or did the Mustangs have better headers ??

Mustangs have "better" heads, upper intake (lower is identical), cam, and headers. those items combined with a different ECU and 19lb injectors make for a roughly 65hp difference (150 vs 215)

the stock mustang headers are better than your stock manifolds, but not by much.

So why couldn't I just add an "h pipe" to my stock engine to go to the flowmaster 44's, maybe some tails, and just be happy with that ?  I don't think headers are gonna change much of the sound that I have. I would probably need to upgrade the engine entirely (cam, push rods, etc...) and don't really have time or $$'s for that stuff.

If I knew of an off road H pipe, or one without cats, that would fit directy I would buy it, but it seems that the "Catco 4179" or the Mark VII pipe has catalytic converters, and probably not high-flow ones.

any h-pipe that will fit a 5.0 fox body will fit your thunderbird, with or without headers

I'm telling you, with an otherwise stock 5.0, cats are not a restriction you need to worry about.  That's like saying "gee whiz, I hope this 0 gauge battery cable isn't too small for my 200 watt amp", or "I just don't know if this fire hose can handle all the flow from the tap on the side of my house".  Even with a stock Mark VII H-pipe at 2" and cats, you're still DOUBLING the exhaust flow potential through THE ENTIRE SYSTEM without drastically increasing the engine's ability to create more exhaust to flow through it.  Until you've got an HO cammed motor with better heads and a better intake, even the complete exhaust from the heads to the bumper from a Mark VII has way more capability than your engine can take advantage of.  The restriction with that exhaust would be the engine itself. 

So in summary, the Mark VII exhaust CATS AND ALL is adequate up to around 250HP, OR 100 horsepower MORE than your engine makes.  And you can get a catless 2.5" H on summitracing.com for $140.

Have you actually bolted a Stang H pipe to a set of T-Bird exhaust manifolds???


The header outlet is far larger and if I remember correctly they are a littler longer and angled differently from the iron manifolds... Got comparison picts on a older computer, but I'd have to dig it out...

Well I did notice a big difference in power and sound when I gutted out my cat and was running the car without any pipes, so basically open headers. I couldn't do that for very long though because it was way too obnoxious sounding, and I work near a state police barracks.....lol. Not to mention it caused the car to run too hot, which led to me blowing a heater core hose. That may have been just coincidence since my hoses are over 25 years old. Something else I need to replace soon :rollin:

 I would prefer to find an h pipe that fits but without the cats. If  I need to extend it a little to the lers that's fine, but it needs to bolt on to the manifolds correctly. It would be kind of impossible to hollow out the cats on the Catco becase they don't look like theyre detachable without cutting. The only option would be to cut them out and weld a piece of extender pipe that would fill the gaps, and maybe offer the cats in trade credit to my mechanic since they do have value.

Everytime you post I wonder if you know what the H-pipe exhaust looks like and what it's made of.  Here's a picture.

Here are three more...

The center H is what I use on the Bird, I tried the X but it's a little shorter and won't fit unless I lengthened the intermediate pipes... Also it interferes with the factory AOD floor shift linkage more so than the H, so wasn't going to happen...

The one with converters is from a '86 LSC, the H is a Hooker & X is unknown...


(http://i1358.photobucket.com/albums/q765/xxAMxx/TurboCoupe50/hpipes_zpsf4f716ad.jpg)

That's the setup I want, but without the cats ....

The Mustang X and H pipes indeed won't bolt up to the cast iron Tbird manifolds.

If  you have to have it smog sniffed, I'd go with cats. Depending on your  state's laws though, it may be old enough to forgo the sniffer, or might  just be a visual check only..

As far as I know, and according to NY state emissions, any car 25 years or older (mine is 25 this year) is exempt from emissions. Not sure about safety checks though.

factory mustang h, yes. aftermarket, no. I have had stock mustang headers bolted to stock t-bird y-pipe before and contrary to popular belief it sealed just fine

But not a Stang H pipe bolted to the factory iron manifolds???(which is what we're talking about)

I can't see any chance of that working, at least without mods to the pipe......

Agreed. When I was transitioning from the LX (http://"http://www.foxtbirdcougarforums.com/showthread.php?35481-Unconventional-Engine-Trans-pull/page4") to the new car, I attempted to run my Mark VII H on the Stock 5.0 manifolds, just because It need some sort of exhaust for the week I had to drive it prior to the powertrain swap, and I'll tell you, the Mark VII H goes with the stock Mark VII headers I had, but NOT the stock MANIFOLDS that were on the STOCK 5.0.  Won't fit in 10,000 years.  The cast manifolds have a 1" wider stud distance, and a 1/2" smaller outlet, not only that but the distance (spread) of the outlets from bank 1 to bank 2 is different.  No H-Pipe will fit up to the stock CAST IRON manifolds.  (if you look at the pics in my link, you can see that the Mark H was up to the cast manifolds, but does not fit, you should be able to see why)
But I'll tell you what:  5.0 Mustang guys literally throw the stock TUBULAR headers away in the trash, and you can pick them up super cheap.  They will fit up to almost ANY H-pipe (any pipe that isn't larger than their outlet flare of about 2 1/4") including, but not limited to: stock Mustang H-pipes (2 1/4), stock Mark VII H-pipes (2"), and any aftermarket H or X pipe (up to 2 1/2") with or without cats.

OKAY...I have a chance to buy a pair of stock Mustang headers from an 1988 5.0 / 302, and the h pipe all for $60 locally. Good deal?? I assume these will fit my 302 but any mods need to be done to the engine ? I know i'll need to lengthen the h pipe a bit too....

All that will bolt up just fine,and it's a good deal to boot.  I still don't think you understand though, that you DON'T LENGTHEN THE H-PIPE. You lengthen the MID-PIPES and you lengthen the TAILPIPES (only if you use larger ones from a Mustang) or run stock tailpipes and stock Mark VII mid pipes. You don't need to TOUCH the h-pipe. Just swap on the headers, put the extended O2 sensors in the h-pipe, and install the h-pipe and hook up the sensors. Done. Slip the s over the Mark VII mid pipes and put the mid pipes up to the ball s at the end of the H-pipe, install 2 bolts 4 washers and 2 nuts per , leave them loose enough for the mid pipe to move around a bit as well as twist. Slip the lers over the mid pipes,put the clamps on but leave them loose. Slip the tails over the axle (this works best with the car jacked up and the axle hanging) put on the clamps and leave them loose. Attach the stock tails to the end hangers with the 2 bolts. Now rotate the mid pipes until the lers are up high in the body and the mid pipe is as far away from the drive shaft as you can get it while keeping the ler up high. If everything looks high and tight, tighten down the bolts at the s, make your last adjustments to the ler's positions and tighten the inlet clamps. Make your last adjustments to the position of the tailpipes, and tighten the outlet clamps. Set the car down start it up, listen for leaks, and if there are none, feel awesome.

And with that, I'm taking as break from this thread before I turn into Tom Renzo.

No worries, there's a difference between arguing with someone, getting all pissed off, threatening to leave, and then deleting all previous posts when called out, as opposed to being factual, un-opinionated, and calm, and cool as you are. :)

yep, install the headers and H-Pipe, and then modify the rest to fit.

If you have a column shifter, you may need to adjust the column linkage a bit for the headers to fit. A non issue. Bolting them on is easy stuff. get new bolts. The exhaust manifold bolts are different lengths. I had grade 8 bolts and lock washers and never had an issue. Or, run down to any parts store and get some header bolts. Smaller head and easier to access with a small socket.

$60 is a great deal. When I had my stock H-Pipe many moons ago, I broke all of the catalytic stuff out and then bolted it on. The stock Mustang parts are way better than the stock stuff you have now, and from all I have read, is good for about 275 to 300 horsepower.

One thing I would like to add to all of this.  If you do not require the shiny 87-93 Mustang LX stainless steel tail pipes then get a set of the 87-93 Mustang GT tail pipes.  Here is the reasoning behind this, the LX tail pipes will hang down below the body of the car and to lengthen them requires additional stainless steel tubing, a tig welder, grinding, and lots of polishing if you want them to be the same diameter.  If you are not worried about the same diameter then you will be adding about 8" of "tip" to the end of the tail pipes similiar to echo chambers.  The GT tail pipes have a slight turn down on the end of them and they will tuck up high so you will not see them.  It is very easy to just have an exhaust shop lengthen them and no one will be the wiser as they are almost hidden from view.  I did this on my 85 Turbo Coupe with a single 2.5" exhaust on the car so I used the driver side GT tail pipe and had it lengthened.  Buddy of mine owns an exhaust shop so he was always willing to try new stuff and had a shiznit ton of Fox Mustang stock exhaust parts piled up to experiment on.

One other clarification would be that the "mid pipe" that is referenced so many times is the short piece of exhaust tubing between the rear s on the H or X pipe assembly and the inlet of the lers.  Again, this piece is very easy to lengthen and with our cars has to be to located the lers correctly.  The T-Birds are longer in the mid section and rear end than a Fox Mustang.

Darren