[pchris]

Hey guys and gals,

Just wondered if anybody recommends the use of H-pipe on an exhaust system for a 69 cat...if so...any ideas on where to purchase said beast or do you make your own.

Thx.

 

[Lab Rat]

H-pipe, good

Here's my $0.02 on the H-pipe:

I've read a lot about straight dual exhaust vs. H-pipe vs. X-pipe, and the general consensus seems to be that the H- or X-pipes will give a performance benefit over straight duals on any engine. The reasoning I've heard is that a connection between the sides allows "evening out" of potential pressure differentials between the two sides due to the timing of exhaust pulses. This allows the exhaust gases to flow more quickly and uniformly through the exhaust system (this is my understanding of it, anyway). Seems a little like voodoo to me, but peformace tuners seem to swear by H- and X-pipes.
Having said that, I would tell you that my experience with an H-pipe is limited to the one that I installed on my wife's '02 'Stang. We got rid of the stock exhaust system with its four (yep - count 'em, FOUR!) catalytic converters and installed long tube headers, a catted H-pipe setup, and a new cat-back, and it totally transformed both the performance and (of course) the sound of the car. I'm in the process of rebuilding a '67 Cougar right now, and I fully plan to put an H-pipe set up on it as well (if I ever get that far). But I suspect that any such installation would have to be a custom job on these old cars. I haven't looked for such parts for our older cars, there are a LOT of parts available for the later model years (late 80's up), and I suspect that those parts are what saturate the market. However - I would think any reputable exhaust shop would be able to weld you a set-up without too much trouble.
Hope this helps - good luck!

Lab Rat

 

[TheRktmn]

If you are using the original exhaust manifolds then the stock replacement header pipe should have an equalizer tube in it (H pipe). At least every stock replacement I ever bought for my 68 and 69 had it.
If you are using aftermarket headers then you can buy X or H pipe kits from most performance shops.
Like LabRat says. they are definitely worth it.

Here's a quote from FordMuscle's article on X pipes:

X Versus H
It's long been known that connecting the two sides of a dual exhaust system, shortly after the headers, increases power and reduces sound. However in a traditional "H" pipe, only sound and pressure waves cross through the connection. Gasses take the route of lowest pressure, which is straight out the pipe, rather than making a 90 degree turn in to the H.
Indy and Nascar teams have been using "X" type crossovers for quite some time. In an "X" pipe the gasses from both cylinder banks actually pass through a common area. This not only provides the benefits of some sound wave cancellation, but also increases the scavenging effect, helping draw out spent charge from the combustion chamber.
So how much of an increase does an X gain over an H? It's hard to say, especially considering that every combination will yield varying gains. In theory an X will work better as rpms go up. Considering the Flowtech X- Terminator pieces are priced under $50; you're much better off getting that, rather than having a shop fab up a crude 'H' piece.

You can read the entire article at http://www.fordmuscle.com/archives/2000/04/flowtech/index.shtml

 

[Lab Rat]

Hey - I hadn't read that one. Thanks Rktmn - that X- vs. H- pipe debate goes on and on amongst the 4.6L crowd. But I never heard the benefits of the X-pipe explained that way before. Cool....

Lab Rat

 

[mercman]

pcchris, I own a muffler shop in MO. h-pipes push the exhaust out faster.. u really only need one if u dont have headers.. Ive had it both ways on my 400 horse 67 cougar,but i didnt like losing the low end power.. h-pipes give u horses,but lose low end..so in my case i have plenty of horses& i mainly like to play hard,tire smoking fun!!!! it also depends what u have in store 4 ur ride? just remember that lose back pressure,lose low end.. 289s have bad response at low end atleast up til 2200rpm or so then its all fun!!!!build it 4 how u want to drive it!!! my 289 runs 12"s at track.. headers,3000rpm stall,411 gears,real power producing 289 k motor goodies,fun,fun! EVEN THE CHEVY HEADS MOUTH WATER WHEN THEY HEAR THIS FIRE UP!!! hope ive helped in some way! LIVE CLOSE GIVE me a call .. I can custom build any exhaust system u need!!! 636- 239-7677 ask 4 rusty..Ive done hundreds of show cars,derby cars,even had dauls on lawn mower! gave a great day!

 

[leonbray]

That's why V8 circuit racecars now have an oval tube section like a muffler, but same cross sectional area as two pipes, just after the headers and under the tailshaft so they can get a better balance of gasses over a wider torque range