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440 HP Exhaust manifolds vs. Headers...
#64433
05/27/08 11:41 AM
05/27/08 11:41 AM
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Joined: Sep 2006
Posts: 164
CH
plyrr69
OP
member
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OP
member
Joined: Sep 2006
Posts: 164
CH
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Hello
I have some Headers in my Runner. I have heard that the original HP Exhaust Manifolds have the performance close to my headers... is there a truth about that, or is it just a story? i am thinking to come close to something like F.A.S.T Cars, original looking with performance... with exhaust manifolds!
___________________________
.......plymouth tells it like it is...!
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Re: 440 HP Exhaust manifolds vs. Headers...
[Re: plyrr69]
#64434
05/27/08 11:51 AM
05/27/08 11:51 AM
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Joined: Jan 2003
Posts: 30,998
Oregon
AndyF
I Win
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I Win
Joined: Jan 2003
Posts: 30,998
Oregon
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I wouldn't say the performance is the same, it is just that you can go plenty fast with manifolds. It is rather easy (given the resources) to build a car that looks fairly stock yet has the ability to run 11.50 at the strip.
If you aren't going to put a roll bar in the car then you run the manifolds. There really shouldn't be too much of a problem of getting a big block with manifolds deep into the 11's.
Last edited by AndyF; 05/27/08 12:03 PM.
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Re: 440 HP Exhaust manifolds vs. Headers...
[Re: plyrr69]
#64435
05/27/08 11:52 AM
05/27/08 11:52 AM
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Joined: Jan 2006
Posts: 1,220
toronto canada
69chargeryeehaa
pro stock
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pro stock
Joined: Jan 2006
Posts: 1,220
toronto canada
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Just my  here but i'm totally done with headers. My 69 charger r/t stock 440, had headers, they leak both at the head and the studs (coolant), higher underhood temps, too much heat for the starter, and they are a TOTAL PAIN IN THE ANUS TO GET IN/OUT. So i got a used set of the HP manifolds and a TTi 2.5 with h-pipe, installed them (which was so easy it wasn't funny, i did it twice just because it didn't feel right!!!!) and the car actually runs MUCH better, i did'nt notice a performance decrease at all. Just for the ease of working with them, and how much eaiser it is to work on the car (plugs, starter, steering box, ect....) i will never run headers again!. 
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Re: 440 HP Exhaust manifolds vs. Headers...
[Re: plyrr69]
#64436
05/27/08 12:22 PM
05/27/08 12:22 PM
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Joined: Jan 2003
Posts: 24,562
Brookeville, Md
Mr.Yuck
Not enough dumb comments...yet
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Not enough dumb comments...yet
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
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Quote:
Hello
I have some Headers in my Runner. I have heard that the original HP Exhaust Manifolds have the performance close to my headers... is there a truth about that, or is it just a story? i am thinking to come close to something like F.A.S.T Cars, original looking with performance... with exhaust manifolds!
no way. The FAST guys sink $$$ into their mani's and if they could they'd all run headers. Not saying you can't run fast with mani's but you'll pretty much always run better with headers. Especially on anything over stock build. I'd leave them on unless you are planning on entering a restrictive class like FAST or factory stock.
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Re: 440 HP Exhaust manifolds vs. Headers...
[Re: Mr.Yuck]
#64437
05/27/08 12:38 PM
05/27/08 12:38 PM
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Joined: Apr 2005
Posts: 15,134
Kelowna, B.C. Canada
DPelletier
I Live Here
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I Live Here
Joined: Apr 2005
Posts: 15,134
Kelowna, B.C. Canada
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Quote:
Quote:
Hello
I have some Headers in my Runner. I have heard that the original HP Exhaust Manifolds have the performance close to my headers... is there a truth about that, or is it just a story? i am thinking to come close to something like F.A.S.T Cars, original looking with performance... with exhaust manifolds!
no way. The FAST guys sink $$$ into their mani's and if they could they'd all run headers. Not saying you can't run fast with mani's but you'll pretty much always run better with headers. Especially on anything over stock build. I'd leave them on unless you are planning on entering a restrictive class like FAST or factory stock.
The FAST guys have all sorts of fancy extrude honing done, but the Pure Stock guys don't.
I think Andy pretty much nailed it. The headers ARE going to give you a performance boost all things being equal, BUT whether it's a minor improvement or a major one depends on the build and power levels.
You really get two separate schools of thought on this question whenever it comes up;
- 1) Headers are always better, why not run them.
- 2) If your goal is X horsepower, it can be done with manifolds.
....it really depends on what you're looking for.
I also think that people tend to forget that the exhaust system works as a system; a nicely done 2 1/2" mandrel bent system with an X pipe, hi flow mufflers and HP manifolds may well flow better than a set of cheapee headers, 2 1/4" compression bent pipes and crappy mufflers.
Dave
1970 Super Bee 440 Six Pack
1974 'Cuda
2008 Ram 3500 Diesel
2006 Ram 3500 Diesel
2004.5 Ram 2500 Diesel
2003 Ram 3500 Diesel
2006 Durango Limited
[url] http://1970superbee.piczo.com [/url]
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Re: 440 HP Exhaust manifolds vs. Headers...
[Re: THESHAKERPROJECT]
#64440
05/27/08 01:35 PM
05/27/08 01:35 PM
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Joined: Apr 2005
Posts: 15,134
Kelowna, B.C. Canada
DPelletier
I Live Here
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I Live Here
Joined: Apr 2005
Posts: 15,134
Kelowna, B.C. Canada
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Quote:
In an old issue of Mopar Muscle the stock manifolds cost 80 HP on a 500HP motor.
That would be inaccurate. There MAY be a 80hp difference on a particular 500hp motor, but it is completely dependant on the build (and more specifically the camshaft). As you mentioned, there are cams out there designed to work with manifolds.
I also agree that the competitive FAST stuff isn't really streetable. Cool, but not practical and that's why I've chosen to go the Pure Stock route.
Dave
1970 Super Bee 440 Six Pack
1974 'Cuda
2008 Ram 3500 Diesel
2006 Ram 3500 Diesel
2004.5 Ram 2500 Diesel
2003 Ram 3500 Diesel
2006 Durango Limited
[url] http://1970superbee.piczo.com [/url]
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Re: 440 HP Exhaust manifolds vs. Headers...
[Re: AndyF]
#64441
05/27/08 01:40 PM
05/27/08 01:40 PM
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Joined: Jan 2003
Posts: 24,562
Brookeville, Md
Mr.Yuck
Not enough dumb comments...yet
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Not enough dumb comments...yet
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
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Quote:
The low deck 470 in my B body car was a fairly inexpensive motor to build. Unported Edelbrock heads, Performer RPM intake, Eddy 800 cfm carb, Mopar Perf .528 solid cam, etc.
With the HP exhaust manifolds and a 3 inch exhaust system it would spin 475 RWHP on the chassis dyno all day long. That is more rear wheel horsepower than a lot of Vettes, Vipers, Mustangs, etc.
That engine idled at 800 rpm with plenty of vacuum and drove around town pretty easily. Compression was 10.5 so it ran just fine on pump gas premium.
475 RWHP will put a B body deep into the 11's if a person has the chassis setup correctly. My car would run low 12's at 115 mph on radial street tires when I took it to the track.
 just think how well it would run with headers and a good carb, like a double pumper!
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Re: 440 HP Exhaust manifolds vs. Headers...
[Re: Stanton]
#64446
05/27/08 04:33 PM
05/27/08 04:33 PM
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Joined: Jan 2003
Posts: 24,562
Brookeville, Md
Mr.Yuck
Not enough dumb comments...yet
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Not enough dumb comments...yet
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
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Quote:
With all the issues there are with headers - rusting, fit, performance, accessability, ease of installation, etc. it makes me wonder why someone hasn't started to produce a decent set of cast manifolds aimed at the street/strip guys. With today's casting technology you wouldn't think it would be that much trouble - cetainly no more labor intensive than welding pipe together.
I don't know why people have some many problems with headers. I've had several sets. Cheapos too. strip them and paint them w/ a good high heat paint and they last a looong time. Don't over torque the bolts and they won't leak, don't drive like a duke boy and they won't drag the ground. leave the mani studs in or use long header bolts w/ a tab of sealer and they won't drip coolant. I don't see why anybody (besides the #'s matching, FAST pure stock guys) would wanna run logs.
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Re: 440 HP Exhaust manifolds vs. Headers...
[Re: plyrr69]
#64447
05/27/08 05:24 PM
05/27/08 05:24 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Talking with Tom at accurate exhaust he told me that there would be very little difference. Most guys out think themselves and don't realize they need back pressure. Tom put together a great exhaust system for me. I also talked with a super stock racer and he said the only place you would see a difference would be top end.Since I don't drag race thats all I needed to hear. I was tired of the heat, low clearence and the engine was hard to work on so there gone.
Thanks Moparts
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Re: 440 HP Exhaust manifolds vs. Headers...
#64450
05/27/08 06:13 PM
05/27/08 06:13 PM
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Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
BradH
Taking time off to work on my car
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Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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Quote:
... Most guys out think themselves and don't realize they need back pressure.
Sorry, but that's crap. Back pressure is BAD; you want as little back pressure as possible in a performance application.
What you have to take into account is most engines (especially in near-stock configuration) aren't tuned for a no/low-backpressure exhaust system. That's why some people mistakenly think that some backpressure is good... because they haven't made the rest of the tuning adjustments to handle an improved exhaust system.
Re: the original question... yes, a good set of headers are definitely worth power over a set of OEM HP exhaust manifolds. As others pointed out, how much depends on a lot of factors. However, on something like a mild-to-moderate 440 street engine, I'd say it's a safe bet that switching from HP iron manifolds to a good set of properly-sized headers for the application would be worth 20-40 HP and a comparable amount of torque.
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Re: 440 HP Exhaust manifolds vs. Headers...
[Re: BradH]
#64451
05/27/08 07:28 PM
05/27/08 07:28 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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1 3/4" headers, theres little difference. 1 7/8" you'll start to notice a difference. 2" headers theres ZERO comparison.
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and what is a good pair of used rusted pitted manifolds goin for these days...$400 or more ?
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