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Discussion Starter · #1 ·
I now have a 302 with 4 cylinders on each pipe (two banks not connected. What gains would see from moving to H pipe?
 

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The 'H' (or 'X') pipe gives you more bottom end torque. It also makes the exhaust sound much better.
 

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I made mine with a removable H pipe.

Benefits:

Power
Lower Noise
Stiffness to exhaust system (no rattles)
Drive Shaft Safety Loop
 

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Discussion Starter · #4 ·
How much difference between sound from H to X and how much power?
Deciding what to go with...
 

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I went with an H pipe for my 302 and it definitely made the exhaust less loud and less raspy (in a good way). I noticed a bit more bottom end also. I had a very experienced exhaust man tell me that X pipes aren't very good for the street. He believed that they gained top end power at a loss to bottom end. I've had others on this board contradict this though.
 

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I am a big proponent on the "X" pipe, if you intend to make this a small block road rocket, I would suggest getting the 2.5" "X" with 2.5" exhaust all the way back from the headers,if you are just looking for good street performance I would still suggest the "X" but the "H" will work just as good and would probably be cheaper
 

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I recently made the swap from an H to an
X on my '68 Mustang. Both systems were
2.5-in front to rear. Big, big difference
in throttle response and bottom-end TQ.
Sounds really good too. And got rid of
quite a bit of resonance inside the car.
Numbers-wise, it is 2db quieter inside
the car at cruise. Outside the car at
cruise it is 10db louder with the X.
 

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Yeah, H pipe seems to make more backpressure, so, ++ on low-mid range torque, X pipe= less backpressure, which is more high end HP and less low-mid range torque, as for the sounds I have no idea.
 

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On 2002-05-09 01:25, BuiltFordTough wrote:
Yeah, H pipe seems to make more backpressure, so, ++ on low-mid range torque, X pipe= less backpressure, which is more high end HP and less low-mid range torque, as for the sounds I have no idea.
I'm not trying to dis anyone or ruffle any feathers, so don't take this personally. I just have to say that increasing exhaust backpressure does not increase low end torque. That's a falacy, myth, old wives tale, whatever you want to call it, that just won't die. An engine that's built and tuned right will always have more low end throttle response, as well as more torque everywhere in the powerband if the backpressure is zero. Exhaust backpressure effects torque adversely at all RPM levels, although the negative effects are greater and more obvious at high rpm. Adding collector length to open headers does often increase low end torque, but it's not because it adds backpressure. It just changes the resonance wave tuning so that it's correct at a lower RPM level. Likewise, the point at which the crossover is installed, especially on a large diameter exhaust system, often becomes the resonant point, and acts just like the end of a long collector. This principle can be used to build more low end torque, but adding backpressure just isn't what does it.
 
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