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barrman :
Re: BBC header selection, what did you use?
Post by barrman on Sept 19, 2006, 9:57am
Mark,
It all depends on what you define "out perform" as.
Aftermarket headers will almost always make more top end power. They will sound better and the engine will probably get better gas milage going down the highway with the cruise set. This is really true of modern efi engines.
But, except for a very few brands and applications that are really expensive. Headers will not "out perform" OEM manifolds when it comes to longevity and leaks. The OEM's concentrate on stuff that will stay bolted on and not cause return issues with leaks. Especially all vehicles made after 1967 when the EPA got their fingers in the exhaust pie.
Many headers will not out perform OEM manifolds when it comes to low rpm high torque situations. I define "low rpm" as 2,000 rpm and lower. As pointed out above, the smaller the valve and exhaust pipe, the more low end torque an engine will make compared to a big exhaust valve and huge exhaust system on the same engine.
Banks and Edelbrock both make CAFE legal headers for the newer stuff. That is a big hurdle to go over. I also think both companies make good products they stand behind and have for years. If you can find something from them that will fit the truck, go for it. I have tried most of the other brands in the past and always wished I hadn't a few years down the road when the headers start to either rust out or burn through. This is not counting the almost monthly chore of re-tightening the headers to the engine, really hard spark plug changes and the always leaking flange gasket that takes about 5 hands to get right.
Then you need to consider the replacement issues. Say bought a hooker set up today. 2-4 years from now when it is all warped, rusted and burned through, you will have to replace them. You didn't like how their product worked and you are going to try the Banks. You will probably have to get different bolts to make it attach to the engine. Then your existing pipe won't match up and probably will have the wrong end on it anyway.
Unless you are going to be drag racing, mud bogging or sand running your M715, I really can't see an advantage to headers on a daily driven street legal truck.
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gimpyrobb :
Re: BBC header selection, what did you use?
Post by gimpyrobb on Sept 19, 2006, 11:28am
Bob, chris works not far from my house and can check the fit with relative ease, But thanks for the heads up on fitment. Chris let me know when (if) you want to swing by to check thm out, I have to get them from my buddy's shop first.
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40grit :
Re: BBC header selection, what did you use?
Post by 40grit on Sept 19, 2006, 11:51am
Tim,
good points, I had a set of Thorley headers on a warmed up 'burb, except for the $@%#$^ collector gasket, I never had a problem with the exhaust gasket...had that truck for 5 years, changed lots of collector gaskets, but never had a leak with the header to head gasket..
don't stock manifolds also keep substancially more heat under the hood also? it would seem all that cast iron would hold in the heat much better than headers?
Anyone had luck with Jet-hot or similar ceramic coatings? I see most of them recommend not using the coating on a brand new motor, they say to break it in with old headers then switch to coated headers, something about not screwing up the coating....
I had real good luck with Thorley's coating, except the SMF at the muffler shop didn't wipe the handprints off the chrome prior to starting the truck so I had these nice burnt on handprints on the headers, but the finish held up well...
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40grit :
Re: BBC header selection, what did you use?
Post by 40grit on Sept 19, 2006, 11:54am
Quote: <TABLE class=bordercolor cellSpacing=1 width="90%"><TBODY><TR><TD width="100%"><TABLE class=quote cellSpacing=0 cellPadding=2 width="100%"><TBODY><TR><TD width="100%">Aftermarket headers will almost always make more top end power. They will sound better and the engine will probably get better gas milage going down the highway </TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE>
Those are important to me...
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elohim1 :
Re: BBC header selection, what did you use?
Post by elohim1 on Sept 19, 2006, 7:56pm
Bob gave me the heads up on Sanderson. I called them today and asked about these manifolds (QP2000). They said they may work on my application.
If they would this maybe the best of both, headers and manifold.
Lets here some thoughts ?
http://www.sandersonheaders.com/prod...products_id=41
(PS, if this link does not work, will someone post it so it will)
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gimpyrobb :
Re: BBC header selection, what did you use?
Post by gimpyrobb on Sept 20, 2006, 7:55am
Those don't look any differant than what I've got from the 366.
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tacomainoh :
Re: BBC header selection, what did you use?
Post by tacomainoh on Sept 20, 2006, 3:18pm
I'll be using Edelbrock shorties. The 454 mockup w/the stockers fit fine and hit nothing. Yay!!!
Elohim, the stock manifolds breathe well enough under 5k that the benefits are going to be minimal with that 502. But if you're swimming in cash, headers look perty... To be honest, the ceramic coating on the shorties I"m going to use is mostly WHY I"m going to use them, as I probably won't have any inner fenders.
Bluesman, FSJ coolant pukers will work fine, and mount to the fenderwell.
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robertcowan :
Re: BBC header selection, what did you use?
Post by robertcowan on Sept 20, 2006, 10:04pm
you can get them sandersons cheaper than that elohim1
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luckypabst :
Re: BBC header selection, what did you use?
Post by luckypabst on Sept 20, 2006, 10:28pm
Sandersons are the bomb. A properly designed iron manifold can run with the tube headers all day long - they're just heavier and more expensive. The big problem is general opinion is skewed by too many magazine articles and lots of low HP exhaust designs from the OEM.
Personally I can't stand the sound of tube headers. There's a definite tinny ring to them where the cast iron is very rigid and will absorb a lot of noise that you'd hear from the tubes.
If I were facing this decision (and could afford it), I'd go with the Sandersons, no questions asked.
Chris
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robertcowan :
Re: BBC header selection, what did you use?
Post by robertcowan on Sept 20, 2006, 11:07pm
ME TOO also add every couple years they rust out, countless amounts of blown gaskets, hard to get to spark plugs , burnt plug wires. on and on .......