Headers vs. Manifolds

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Jun 2, 2009 | 12:19 AM

vtwinspring

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Intermediate

Joined: May 2009

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From: Hollywood Florida

Headers vs. Manifolds

I hate the sound of exhasut leaks and it seems with headers I am always going to have that problem. How much HP will I lose by switching back to manifolds. What is the noise level difference?

I am running a 350 sb with a mild cam.

Jun 2, 2009 | 01:46 AM

narlee

Melting Slicks

Joined: Apr 2008

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From: Western Washington

Are they full length or shortys? If they're shorties and you use 2 1/2 ramhorns not much at all, especially with a mild cam.

Jun 2, 2009 | 01:48 AM

ghostrider20

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Joined: Jan 2002

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Not enough to notice.

Jun 2, 2009 | 09:04 AM

mashinter

Drifting

Joined: Oct 2008

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From: Rochester Hills Michigan

Car Craft did a dyno study on a truck 350. Cat-back increased power. Headers did nothing.

Jun 2, 2009 | 10:07 AM

Kensmith

Le Mans Master

Joined: Mar 2005

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From: Rocklin California

Quote:

Originally Posted by vtwinspring

I have the original 2 1/2" manifolds on my small block 383 stroker and 2 3/4" Allen's sidepipes. I ported the manifold to match the exhaust ports on my Dart Pro 1 aluminum heads. Sounds great and runs better than it sounds.

Jun 2, 2009 | 11:12 AM

oldandtired

Heel & Toe

Joined: Dec 2008

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From: Sugar Hill Georgia

Are they leaking at the head or at the collector? The use of embossed copper gaskets will fix your head to header leak. I always convert my three bolt flange collector to the ball flange kit. Never had luck sealing the darned three bolt deal.

Jun 2, 2009 | 12:42 PM

toddalin

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Joined: Oct 2000

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From: Santa Ana CA

Definitely a step backwards in the performance department both for power and fuel economy.

Use better header bolts that you can get a wrench on/Allen key in.

Jun 2, 2009 | 02:02 PM

66since71

Melting Slicks

Joined: Jun 2006

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From: DFW

From the team that did the ZZ series engines at the old GM: They showed a "significant" improvement in power with 1 3/4 x 28" primary tube headers. (I think those dimensions are right, but it may have been 26" long.)

Harry