Power loss from removing headers?
Thread Starter
Safety Car
Joined: Jun 2004
Posts: 4,023
Likes: 1,181
From: La Mesa CA
Power loss from removing headers?
I have a 71 350. Base engine. It is pretty much all original except for having headers. I got the original exhaust manifolds from the previous owners. The headers are older and either have a small leak or there is a small exhaust manifold gasket leak. If I took off the headers and put the stock exhaust manifolds back on, what kind of power loss would I be facing?
Thanks
Glenn in San Diego
Thanks
Glenn in San Diego
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
I have a 71 350. Base engine. It is pretty much all original except for having headers. I got the original exhaust manifolds from the previous owners. The headers are older and either have a small leak or there is a small exhaust manifold gasket leak. If I took off the headers and put the stock exhaust manifolds back on, what kind of power loss would I be facing?
Thanks
Glenn in San Diego
Thanks
Glenn in San Diego
That depends on the intake and cam and lifter setup. If everything is stock except for the headers then you will see a minimal decrease. If the rest is all modded with the exhaust you'll be stopping up the air pump so to speak, and you will see a large decrease.
Intermediate
Joined: Jul 2006
Posts: 43
Likes: 0
From: Ft. Campbell, KY GA
Just depends on the entire system. If you have a stock intake/exhaust on then the gains it's producing are minimal since its not getting additional air in and the stock exhaust would be restricting airflow anyways. However, if you were moving an increased amount of air through due to wider exhaust or bigger intake then it'd greatly restrict airflow.
Thread Starter
Safety Car
Joined: Jun 2004
Posts: 4,023
Likes: 1,181
From: La Mesa CA
Everything is stock.
If I put the original exhaust manifolds on, is their any value on putting a less restrictive exhaust, ie mufflers and pipes. It does need a new exhaust
Glenn
If I put the original exhaust manifolds on, is their any value on putting a less restrictive exhaust, ie mufflers and pipes. It does need a new exhaust
Glenn
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
The manifolds will flow okay through less restrictive pipes and mufflers. Maybe a true dual 2.5" system with dual Flows or Magnas.
Le Mans Master
Joined: Jan 2007
Posts: 7,819
Likes: 3,200
From: Omaha NE
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2023 C3 of the Year Finalist - Unmodified
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2020 C3 of the Year Finalist - Unmodified
Looks like you can get a complete 2 1/2 inch system with Magnaflows from Corvette Central for around $320. I put one on last year and couldn't be happier.....
Le Mans Master
Joined: Jan 2007
Posts: 7,819
Likes: 3,200
From: Omaha NE
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2023 C3 of the Year Finalist - Unmodified
2022 C3 of the Year Finalist - Unmodified
2020 C3 of the Year Finalist - Unmodified
Sounds like a '60s Vette now. I LOVE it. Deeper sound then stock but not much louder......
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Intermediate
Joined: Jul 2006
Posts: 43
Likes: 0
From: Ft. Campbell, KY GA
The power difference depends on the car and I'm no vette expert. I know on my Acura changing the exhaust pretty much just changes the sound and adds almost no power but an aftermarket exhaust with or without aftermarket exhaust produces significant gains.
The sound quality should improve. Listen to some clips online or check em out in person. Good luck man. Let us know what you do.
The sound quality should improve. Listen to some clips online or check em out in person. Good luck man. Let us know what you do.
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
Glenn
Less than 15 is a good estimate for your stock setup. Duals w/ Dynomax or other high flow mufflers & crossover pipe rec. More cam could get more than that HP back.
The more hp one has the more headers help.
Less than 15 is a good estimate for your stock setup. Duals w/ Dynomax or other high flow mufflers & crossover pipe rec. More cam could get more than that HP back.
The more hp one has the more headers help.
Melting Slicks
Joined: Oct 2005
Posts: 2,056
Likes: 8
From: Redruth Cornwall
You say the exhaust needs replacing and you want it to sound louder, also you have a leak in the headers...
Why not just go for new headers with a dual 2 1/2 system, perhaps with an H pipe? That way you can upgrade other components later on for the HP increase.
Why not just go for new headers with a dual 2 1/2 system, perhaps with an H pipe? That way you can upgrade other components later on for the HP increase.
Drifting
Joined: Jul 2006
Posts: 1,871
Likes: 6
From: Sault Ste. Marie Ontario
If your budget is restricted, just fix the header leak and replace the bad exhaust components. Upgrade the entire system when time and money permits.
Thread Starter
Safety Car
Joined: Jun 2004
Posts: 4,023
Likes: 1,181
From: La Mesa CA
You all are right.
Money is an issue.
Otherwise I would be asking about chrome header sidepipes
Plus the rest of the car is stock at this point, so I was just wondering what putting on those stock manifolds, and making it completely stock in the engine compartment, would do.
I definitely don't want to keep the stock mufflers though
Glenn
Money is an issue.
Otherwise I would be asking about chrome header sidepipes
Plus the rest of the car is stock at this point, so I was just wondering what putting on those stock manifolds, and making it completely stock in the engine compartment, would do.
I definitely don't want to keep the stock mufflers though
Glenn
