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440 HP Exhaust manifolds vs. Headers...
Posted By: plyrr69
440 HP Exhaust manifolds vs. Headers... - 05/27/08 03:41 PM
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!
![Attached picture 4454804-Amibilder245[1280x768].jpg](https://board.moparts.org/ubbthreads/upload2/4454804-Amibilder245[1280x768].jpg "4454804-Amibilder245[1280x768].jpg")
Posted By: AndyF
Re: 440 HP Exhaust manifolds vs. Headers... - 05/27/08 03:51 PM
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.
Posted By: 69chargeryeehaa
Re: 440 HP Exhaust manifolds vs. Headers... - 05/27/08 03:52 PM
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!.
Posted By: Mr.Yuck
Re: 440 HP Exhaust manifolds vs. Headers... - 05/27/08 04:22 PM
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 $$$ into their mani's and if they could they'd all run headers. Not saying you can't run fast with mani's but you'll pretty much always run better with headers. Especially on anything over stock build. I'd leave them on unless you are planning on entering a restrictive class like FAST or factory stock.
Posted By: DPelletier
Re: 440 HP Exhaust manifolds vs. Headers... - 05/27/08 04:38 PM
Quote:
Quote:
Hello
I have some Headers in my Runner. I have heard that the original HP Exhaust Manifolds have the performance close to my headers... is there a truth about that, or is it just a story? i am thinking to come close to something like F.A.S.T Cars, original looking with performance... with exhaust manifolds!
no way. The FAST guys sink $$$ 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
Posted By: THESHAKERPROJECT
Re: 440 HP Exhaust manifolds vs. Headers... - 05/27/08 04:53 PM
In an old issue of Mopar Muscle the stock manifolds cost 80 HP on a 500HP motor. I think with a full exhaust the differance may no be that much but a GOOD set of headers will alway make more power. Some FAST cars have cams with wide LSAs to help make power with the restrictive exhaust manifolds...Most of the faster ones have higer compression like 14 to 1 and run on race gas only. I really like the stock look of these cars and there amazing performance but the faster ones are not every day drivers and are far from stock.
Posted By: AndyF
Re: 440 HP Exhaust manifolds vs. Headers... - 05/27/08 05:35 PM
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.
Posted By: DPelletier
Re: 440 HP Exhaust manifolds vs. Headers... - 05/27/08 05:35 PM
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
Posted By: Mr.Yuck
Re: 440 HP Exhaust manifolds vs. Headers... - 05/27/08 05:40 PM
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!
Posted By: AndyF
Re: 440 HP Exhaust manifolds vs. Headers... - 05/27/08 05:43 PM
It would be fairly easy to "cook the books" in a headers vs. manifold shoot out but just selecting a camshaft with a bunch of overlap. The high overlap cam will do pretty good with open headers on a dyno but would be a real dog with the more restrictive manifolds.
I'd say it would also be fairly easy to take the same identical engine and only change the camshaft and have a completely different test result.
Posted By: DPelletier
Re: 440 HP Exhaust manifolds vs. Headers... - 05/27/08 06:30 PM
Yeah, that's what I was thinking.
Dave
Posted By: Stanton
Re: 440 HP Exhaust manifolds vs. Headers... - 05/27/08 07:06 PM
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.
Posted By: dogdays
Re: 440 HP Exhaust manifolds vs. Headers... - 05/27/08 07:37 PM
Sanderson makes cast iron headers for chevy smallblocks. I saw a pair on a '34 chevy coupe a week ago. More interesting to me were the forged aluminum suspension arms of the Corvette rear end. It looked mighty sanitary.
R.
Posted By: Mr.Yuck
Re: 440 HP Exhaust manifolds vs. Headers... - 05/27/08 08:33 PM
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.
Posted By: Anonymous
Re: 440 HP Exhaust manifolds vs. Headers... - 05/27/08 09:24 PM
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
Posted By: THESHAKERPROJECT
Re: 440 HP Exhaust manifolds vs. Headers... - 05/27/08 09:31 PM
and what is a good pair of used rusted pitted manifolds goin for these days...$400 or more ?
Posted By: 1Fast340
Re: 440 HP Exhaust manifolds vs. Headers... - 05/27/08 09:33 PM
Quote:
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
pleace explain the real facts about why a fourstroke engine needs backpreasure?
long tube headers only making an improvement in highrpm power? dont realy believe in that one either please someone show some facts about it..
i fully understand if the benefits of headers are not worth the heat, groundclearance, sound or other obstacels but those things above are not anything i would fully trust, sorry if it looks like i look like bad guy in this post i just don get this...
Posted By: BradH
Re: 440 HP Exhaust manifolds vs. Headers... - 05/27/08 10:13 PM
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.
Posted By: Anonymous
Re: 440 HP Exhaust manifolds vs. Headers... - 05/27/08 11:28 PM
1 3/4" headers, theres little difference. 1 7/8" you'll start to notice a difference. 2" headers theres ZERO comparison.
Posted By: DaytonaTurbo
Re: 440 HP Exhaust manifolds vs. Headers... - 05/27/08 11:47 PM
Headers will always make more hp and torq. How much depends on the rest of the combo. Now you can make a lot of power with manifolds and go quick down the 1/4 with them, however if you're wanting to get everything possible out of your combo(and not willing to pay stupid high $ for OEM hp manifolds) chances are you'll have headers on there.
Posted By: DPelletier
Re: 440 HP Exhaust manifolds vs. Headers... - 05/28/08 03:28 PM
Quote:
Headers will always make more hp and torq. How much depends on the rest of the combo. Now you can make a lot of power with manifolds and go quick down the 1/4 with them, however if you're wanting to get everything possible out of your combo(and not willing to pay stupid high $ for OEM hp manifolds) chances are you'll have headers on there.
....Which brings us back to the point I made earlier. Which is better? It depends what you are looking for.
- Do headers make more power than HP manifolds? Yes
- How much more power will I make with headers? Impossible to say without full specs. Will vary depending on the build.
- Can I make 500hp using HP manifolds. Yes
If you are on a budget and want the most HP for the least $$$'s, then use headers. If you are building a race car, use headers. If you want a strong street car and want it to look stock or don't want some of the alleged hassles of headers then you CAN get boatloads of power out of the HP manifolds as Andy has so clearly demonstrated.
Dave
Posted By: 383man
Re: 440 HP Exhaust manifolds vs. Headers... - 05/28/08 08:00 PM
I myself have always had good luck with headers. I have had the same headers on my sons Dart since we put it on the road in 1997 and it has never had a leak and they still look good. The same goes for my 63 but its only been on the road for almost 2 years.
But like was said it just depends on what you want. I like headers because I have to build cheap combo's and I need the hp headers gives me. But if someone can get the 500 hp or whatever they wany with manifolds then they wont need headers if they are happy without them.
I was thinking about getting the Max Wedge manifolds as to me they look like they might flow as well as headers. But they cost way more then my Headman's and the cast iron manifolds are much heavier. And any drag racer knows weight slows you down.
Ron
Posted By: BadFishy
Re: 440 HP Exhaust manifolds vs. Headers... - 05/28/08 08:47 PM
I sold my set of rusty pitted manifolds on eBay to some guy in Sweden for obscene money IMO, but he just had to have them. Then I bought a set of the repro manifolds for my 440 Cuda from Year One. They fit perfect and look brand new. The only difference I could find was a "Y1" cast in the back side and you can't see it when mounted. They have other castings for that original too. I have had them on for about 2 1/2 years now and they are just beginning to surface rust, so I pulling tham at the end of the show season and will have them ceramic coated cast iron grey for about $150. I could do a permanent coating myself, but for that money, why?! I am sure you would like them as much as I do, and I believe there is a Year One code floating around that is good for 20% off, which would bring the price down below $300. I know I could have bought used somewhere, but I like the fact that 1)new 2)no pits 3)no cracks 4)no looking through swap meets, and 5) comes with all the hardware, etc. I did remove the heat riser and sold that on eBay too! What a country! See the pic.
Posted By: plyrr69
Re: 440 HP Exhaust manifolds vs. Headers... - 05/30/08 06:45 AM
for me its defenetly clear, i want much HP and no Headers, because i like the understatement!!!
But if my car is slow machine after that.... hmmmm, i maybe dont like it! i thin it should go up something in between 11 and 12's with slicks...
what kind of setup you would run?
tx
Dave
Posted By: Silverbullet2
Re: 440 HP Exhaust manifolds vs. Headers... - 05/30/08 10:25 AM
It's always been my theory if you're running a full exhaust, by the time it gets all the way down the head pipes, through the mufflers, over the axle and out the tailpipes it doesn't know whether you had headers or not.
Race car with open or no exhaust system, I'm sure headers are worth some hp, and have the scavenging effect to boot. I still hate to look under the hood of a nice mopar and see a bunch of crappy aftermarket parts.
Posted By: dwbiggs
Re: 440 HP Exhaust manifolds vs. Headers... - 05/30/08 02:47 PM
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.
475 to wheels...nice. How does this cam compare to the one in my sig below. Sounds like the solid is at least as tame...but seems like it would make more HP.