Author Topic: 2 1/2" OR 3" PIPES  (Read 2600 times)

Offline low budget

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2 1/2" OR 3" PIPES
« on: April 27, 2009, 04:36:04 PM »
I am going to replace the exhaust pipes on my 86 LWB 305.  I am going to put a 350 in it when I get the money.  I am going to put headers on it, and don't know which to go with.  I'm leaning toward the 2 1/2" but want to get advice from the guys that have done it before.  I have access to both, just need to get the pipe bent.

Thanks for your help!!!
86 Chevy LWB 305 scrapped for 350, 3/5 drop

Offline VileZambonie

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Re: 2 1/2" OR 3" PIPES
« Reply #1 on: April 27, 2009, 04:43:49 PM »
2.5"
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Offline Captkaos

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Re: 2 1/2" OR 3" PIPES
« Reply #2 on: April 27, 2009, 05:14:50 PM »
Ditto

Offline low budget

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Re: 2 1/2" OR 3" PIPES
« Reply #3 on: April 27, 2009, 05:23:21 PM »
Thanks!
 I'll go with the 2.5"...
86 Chevy LWB 305 scrapped for 350, 3/5 drop

Offline Jay2D2

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Re: 2 1/2" OR 3" PIPES
« Reply #4 on: May 22, 2009, 08:54:33 PM »
And how does 2.25 rank up when running true duals?

Offline Irish_Alley

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Re: 2 1/2" OR 3" PIPES
« Reply #5 on: May 22, 2009, 11:38:25 PM »
use a "x" or "h" pipe when you do it. you will probably go back and do it anyway for better performance
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When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline low budget

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Re: 2 1/2" OR 3" PIPES
« Reply #6 on: May 23, 2009, 04:04:54 PM »
I have heard that before, but don't know why it works so much better.  Guess I need to study it out...
86 Chevy LWB 305 scrapped for 350, 3/5 drop

Offline Irish_Alley

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Re: 2 1/2" OR 3" PIPES
« Reply #7 on: May 23, 2009, 11:14:07 PM »
I'm not sure if I'm right but the cross overs give it more back pressure and makes one side work against the other that also cause more back pressure not sure if its true but its what makes sense to me lol ::)
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

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Offline VileZambonie

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Re: 2 1/2" OR 3" PIPES
« Reply #8 on: May 24, 2009, 12:09:05 AM »
The X pipe helps balance the exhaust pulses. It also helps create a better exhaust tone. The H pipe won't really help with flow but is better than nothing since X pipes can really get in the way with some configurations.
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

Offline low budget

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Re: 2 1/2" OR 3" PIPES
« Reply #9 on: May 24, 2009, 11:05:51 PM »
I read some on this last night.  The H pipe equils the pressure between the 2 pipes, and the X does the same thing with better flow thru.  The X is the next best thing to running straight headders.  Thanks for the reply's.
86 Chevy LWB 305 scrapped for 350, 3/5 drop