anyone see the new HRM big block header comparison? i know it's just a magazine article, but it could give some of you something to think about when choosing headers for your big block. the 2" tubes supposedly performed better even on the stock 454 crate motor they used to test them on. when they added more cam the the difference was even more noticable. the 2" tubes lost only 3 lbs-ft below 4100 to 1 3/4" headers but gained an extra 14hp above that. and that was with the stock cam. with a larger cam it picked power everywhere with 25hp at the peak. graemlins/thumbsup.gif

Yeah, saw the article.
Loved the fact that the pictures didn't match the tube size.
Some real graphs would have been nice as well.
Along with a test of equal length headers vs. unequal length headers.
Ron

The 2" peaked with 557@4100,,,the 1.75" peaked with 560@4400...so they went higher into the rpm range than 2" headers. Like Ron said I wish we had the full graph,but if smaller tubes peak at a higher rpm range,thats good enough for me and my "heavy chevy" I'd like to see the difference down lower in the rpm range.

that was with the stock cam though. when they upgraded the cam, the 2" headers made more power everywhere, more average and more peak. at least according to their tests.
if you get a chance to read the article you should. they are claiming that tube size doesn't affect the powerband of the engine near as much as collector length and camshaft size. but even on the stock cam, i would be willing to give up 2 or 3 lbs-ft of torque to gain 14 or 15 hp at relatively the same rpm ranges. graemlins/thumbsup.gif

With all the talk of header size, its great to see a scientific comparo. As I suspected , its no big shakes at all.

Unfortunately with all the missing data I wouldn't call it too scientific, although it showed some data that is interesting if it can be trusted.

I agree with Gene.

Seems like the difference wouldn't be worth a new set of headers from the best to the worst.

I doubt you'd see much difference in E.T. for 14 h.p., and you'd never notice the difference on the street.

Hot Rod = Advertisers....since everyone has been going the smaller tube route,they had to do an article trying to say large tubes were equal to small tubes...warehouses are full of 2" tube headers,and they need to move some stock. graemlins/thumbsup.gif


ya never know, maybe they'll print all the facts.

i would agree that the difference isn't worth buying a new set of headers over, but if a guy is in the planning stages, it's just something to consider, is all i meant. and that was a STOCK 454 HO, most guys on here don't have an engine that mild. the more cubes, cam, and compression you have the more you'll be able to take advantage of the 2" tubes. and if they were trying to sell anything in the article, it was the 18" collector extensions, not the 2" headers. a month or so ago they had an intake comparo between the victor jr and an rpm on the same motor. the rpm intake was a better overall choice, so i wonder whose inventory they were trying to sell there? Edelbrock's or Edelbrock's? lol!

You guys really believe these magazines?

Do you Really believe that these people want to Give away Good, useful, information? They just want to get you fired up thinking you need what they're selling.

its funny how now matter what magaazine, no matter when or where, no matter what test, no matter the results, people seem to find a way to show how " the magazine lied" I GUARANTEE that the people who are debating this would get all excited and happy if the test showed that small tube headers worked way better than the big's. I bet they would be saying "Told you so!" Now i agree that magazine articles don't always hold their credit, but common is everything fraud? i think the test seemed farely accurate but did lack detail, and how would anyone know how many sets of 2" BBC headers are sitting in the wherehouses across the U.S.?

The small tubes produced more torque up to a peak@4400,the big tubes less torque to a peak@ 4100...nuff said smile.gif Like I said before I'd like to see the whole chart from idle to peak, then we could gloat :D

i myself kinda followed along on the intake story and made a decision on the intake i was going to try based on there magizine artical.

i had a torker 2 intake on my bbc 396 and after reading and looking over the charts i decided to try the rpm intake to see if there would be a better e.t and mph at the track.....well i will say guys i went faster e.t wise (13.92 to a 13.68) with just a plain intake swap with no changes....my bottom end was stronger and my 60 ft times dropped.....but i didnt get no real mph increase tho. about a .5 mph gain (from 104.135 to 104.60)......after a jet increase i did get about another mph gain to 105.454 mph.....

all said and done there was about 13 hp more to the ground with intake and jet change over the torker and that my friends shows on the time slip and you could feel it in the seat of the pants even before i went to the track.

you have to remember that the increase even small is all in the power curve that pushes the car faster and quicker just not the peak numbers....

as far as the headers goes.......i think if they was used on a smaller bbc like the 396 or 427 motor would would see a much bigger difference in the power curves.....

i have for one tried 2" headers several times on a bbc 396 only to pull them back off because the car ran slower and lost mph.....at the worst point 1 second slower and 8 mph down because of just headers......

but on a 454 with a mild cam i can see why there wasnt much difference the breathing of that motor is just limited on the cam and heads and compression ratio......i would still run small tube headers tho for it has been proven by many bbc racers that small tube headers are even good enough for 10's, even on my 468......i have the cheap summit headers would i see a gain from bigger tube headers proberly. but how much not sure til i try.....

Originally posted by Rapid Robert:
The small tubes produced more torque up to a peak@4400,the big tubes less torque to a peak@ 4100...nuff said smile.gif Like I said before I'd like to see the whole chart from idle to peak, then we could gloat :D yes they did produce more torque, like 2 lbs-ft, while giving up 14 hp, on a stock motor. yes there are guys running 10's on 1 3/4" bbc headers, shoot i know of a couple sbc's that are in the 10's on 1 5/8" headers, but it doesn't mean that they wouldn't go faster with slightly larger headers. they did give average hp and torque figures, not just peak figures. i know a magazine isn't the best source for this type of info, but i don't see anyone else testing and showing the "true" difference. i also agree that a 396 or a 427 are entirely different than a 454, they don't have a 4" stroke. ;)
actually the way the test was run the 1 3/4" headers should have walked all over the 2" headers according to popular belief. you can't get a much more mild 454 than what they tested, yet their tests didn't prove that. tongue.gif

As Bob said, the numbers dont add up.

I wouldnt believe it unless i was performing the test, after all, they have an agenda!

If 2" headers worked best, you'd see them on this Gold Camaro!

Originally posted by Motor Martyr:
As Bob said, the numbers dont add up.

I wouldnt believe it unless i was performing the test, after all, they have an agenda!

If 2" headers worked best, you'd see them on this Gold Camaro! you have 1 3/4" on a small block? that's about the same thing as 2" on a 454. ;)

I have 1-5/8" on my small block!

Torque is what moves these heavy cars. I'll take as much as I can get anyway I can get it. Shifting at 6000 rpm I don't need larger tube headers. Heck I'm probably shifting at a higher rpm than I need to. I need to invest in a bigger tach, I like the stealth look of the smaller black tach,just makes it harder to hit the shift exactly the same all the time.

oops! i see that now. hmmm...maybe you should try some 1 3/4" headers on your small block! lol!

Originally posted by Rapid Robert:
Torque is what moves these heavy cars. I'll take as much as I can get anyway I can get it. Shifting at 6000 rpm I don't need larger tube headers. Heck I'm probably shifting at a higher rpm than I need to. I need to invest in a bigger tach, I like the stealth look of the smaller black tach,just makes it harder to hit the shift exactly the same all the time. that's exactly right Robert,and your motor is nowhere near as stock as a crate motor 454HO, so if you could gain more torque with 2" headers, wouldn't you try them? your combo works pretty well, but if the 1 3/4" headers are what's making all your torque, how come my 454 went 1.58 60 ft with 2" tubes and a single plane intake, and a much larger cam with about the same convertor you have? doesn't seem possible by your logic. ;) one thing i've learned is that you've got to keep an open mind, and that doesn't just go for drag racing or hotrodding. it's a hard thing to do, especially when something has worked well for you for quite some time.

I did extensive research and found the 1 3/4" to be best for my EXTREMELY MILD 454. I hope to get into the 12's @ 3600# For the street you just don't need huge pipes.

Originally posted by m71:
oops! i see that now. hmmm...maybe you should try some 1 3/4" headers on your small block! lol! Actually, if i try anything on this small block it will be 1-1/2" primaries, that are 34-36" long.

Its Quite simple if you want a real header comparison, head out to the Race Track and watch what the Stockers, turning over 7500rpms, with 5.13+ rear gears, and 8" converters use on their cars in MY ET range.

At some point, the opening in the header is going to be smaller than the port you are matching it to.
Right?
So are you telling me that this will improve torque? By plugging up a quarter of the port opening?

Wouldn't it be as interesting to flow the head with a bunch of different tube sizes, then compare this to real world dyno and drag strip tests?

I'm betting that 1.5" headers will suck on your car MM.

Ron

Brian do you fellas base all of your facts on "stockers" i mean they are great and all, but they aint the only cars that go fast. and too what was that post about "if they worked you would see them on my gold camaro" wow that sounds familiar, where have i hear stuff like that before smile.gif . I mean i have heard you and ed say that about a lot of things, saying that you would have them on your car if they worked, but.... they were never on your car to prove they didn't work! and to put 2" primarys on a 450hp small block? I think that there are a couple of ways of doing things. It seems you BSE guys have found a way of doing things that people have been doing for years now. It does work, and you guys have proved it. Butttttt there are also other ways to do it that are just as good and some times easier. I think that it is good to have a different point of view and a different way of doing things, and am glad you can put your input here, but we don't tell you that your way won't work because you have proved it works. There are plenty of people here who have done it the "other" way and have proved big stuff or "moderatly" big stuff also work. And i don't think it is fair to discredit every single magazine article on earth just because it doesnt' jive with your theory. Obviously we all know that magazines are about advertising. But they are gearheads also and I don' tthink they have a conspiracy going. YOu just have to read them with a level head.

A stock eliminator car is the closest comparison to a street/strip car that you will find.

Malibu71,I had 2" Hooker Comp headers on my car originally,and besides the fact that the collectors and lower tubes kept dragging the ground, I was never able to get my car in the 11's. My best with those was 12.04,the following winter I switched to the dynomax 1.75" coated headers and finally got my 11 sec. timeslip 11.95-11.97,with more tuning and Hoosier slicks I was able to muster my best of 11.78,last july it was 11.85 with drag radials thru the 3" exhaust. Here lately I cannot buy an 11, I think its gettin tired,been in the car for over 5 yrs,3 yrs full time racing plus numerous TNT nights,with well over 700 passes and the occasional lead foot on the street.

Guys, please bear in mind that the peak header torque calculation involves the area of the header tube as well as the volume of the cylinder, so you can't make linear comparos like 2" on a 454 is equal to 1.75" on a 350, or such like that. With area calcs, as you all well know, a little chamge in ID menas a big change, same as cylinder volume.

In a 427 peak header torque is around 5100 with 2" tubes, well above what most bbc engines are BEGINNING to make great pwoer at. In a 454 that drops to about 3900 rpms, where 1.75" would be around 3000 rpms, for example.

Suppose to gain .05 sec is important to a bracket racer, however, if you get "stuck" with 2" tubes on a 454+, it isn't the end of the world. As I've said before, throw an X cross in the system, seems like it lowers the peak torque some, yet keeps all the 7000 rpm power.

With flaws and all, still good to see a back-toback comparo between the tube sizes. More data, not hyperbole, would be helpful. Would still like to quantify 'best fit" header size to see how much one "gives up" by using incorrect sizing due to fitment, availability, etc.

( http://www.chevelles.com/forum/ultimatebb.php/topic/4/22121.html)

high winding 327's like 1.75" primaries smile.gif

Yup, just like high spinning 427's seem to like 2".

Originally posted by Rapid Robert:
Malibu71,I had 2" Hooker Comp headers on my car originally,and besides the fact that the collectors and lower tubes kept dragging the ground, I was never able to get my car in the 11's. My best with those was 12.04,the following winter I switched to the dynomax 1.75" coated headers and finally got my 11 sec. timeslip 11.95-11.97,with more tuning and Hoosier slicks I was able to muster my best of 11.78,last july it was 11.85 with drag radials thru the 3" exhaust. Here lately I cannot buy an 11, I think its gettin tired,been in the car for over 5 yrs,3 yrs full time racing plus numerous TNT nights,with well over 700 passes and the occasional lead foot on the street. ahh, Comp is the key word there. you should've tried the 2" SUPER COMPS with equal length tubes and better collectors. much better fitting headers too. for as good as the super comps are on most cars the comps are about as equally bad, IMO, especially when it comes to big block stuff.

Originally posted by 427L88:
Hey, Ed and I aren't friends, too much trouble between us, BUT, he is a
very good SCIENTIFIC bracket racer. If 2" tubes would give a better ET,
I'm sure he would have used them. I don't know if he ever tried them,
and he might not admit to it anyway. But, since his game is all in the
short time, bigger pipes won't help.

I know my little street mill lost "off stoplight" torque when I put new
2" Hookers on vs the rusted POS small tubes the car came with.

For a second opinion, theres a nice website www.headerdesign.com (http://www.headerdesign.com) I
beleive.

For the record, dyno numbers dont mean jackcrap to me, and many others.
Not empirically translatable in a live chassis. Further, I SUSPECT (
meaning don't rightly know) that 2" pipes will give better dyno number,
peak HP etc. Again, not 'real-world' performance in a chassis loaded
down with equiptment and a full exhaust.

Again, I'd be curious as to a real live ET comparo, taking into
consideration the motor's operating range.

Anyone got one?

--------------------
Gene
ACES 3112/Team Chevelle Gold #62
CanAm Chevelle Club Ltd.

Old Red 1967 3X2-427 Rat

Be big, be a 'builder'!
Gene, this is one of your older posts on this very topic, i think that what you said here is good.
What made you reconsider the topic?

Hi, I'm the magazine guy that wrote that story. Off the record, I wanted to let you know that I made sure to leave out information and to intentionally lie to you to get you to buy the headers that were in stock at Hooker rather than the ones that really ran best. I got a nice little bonus check for that. It's not like our dyno testing can ever be trusted, anyway. We just make up most of the numbers.

Some of you guys are hilarious. Better watch out for the black helicopters, because they're coming for you.

DF

Oh really.

Tell me, did you measure the length of the primary tubes on each of the headers before drawing a conclusion?

Were the header tubes equal length to begin with?

What length were they?

What lengths were the collectors?

Were all the collector designs the same?

Were all the header flanges port matched to head?

were there an equal amount of bends, similar degree to the bends in each of the header tubes to their respective cylinder in comparison to the others?


Feel free to enlighten me to these little tid-bits of information that have a PROFOUND effect on power.

Before trivialize my opinion i'd like to know this information.

If you want to do a REAL header comparison in a street/strip car send me the tubing and flanges, i'll build them all the same from 1-3/8" in 1/8" steps all the way to 1-7/8" and do same day testing with a control car in the opposing lane!

lol.....freiburger is funny......keep articals like that comming thou.....weather or not some belive them or not.....it is always good to read articals of such to be informed of the possabilities of what can be expected.

like i said in a earlier post i followed the intake dyno on that 454.....and i based my decision on what i saw.....it showed the rpm intake was better then the torker which i had.........i wasnt expecting to get the full 20 or more hp gain out of it or the 30 or more ft lbs of torque out of it down low......i was expecting a alittle more performance from what i had.......without that artical it would have been tougher to make an informed decision on which intake might be better then what i had.

just keep articals like this alive it is good information to read.

I'd like to keep things civil, but i dont like being trivialized because i dont believe everything i read.

I would just like to see the whole graph on each test Freiburger. I know...not enough room between the ads. :D I let my current subscription to HR expire,seems the same articles end up in every magazine they own.

why is it that when someone differs in opinion so many of you take it personally? if a guy has some proof to contradict what HRM published, i'd love to see it. but all i've seen before my eyes as evidence is the HRM article and my own personal experiences.
i just went from 1 5/8" headers to 1 3/4" headers on my small block 406, and although i never got any track time with the 1 5/8", i could tell a difference immediately in throttle response and how quick it revved as soon as i started it up with the 1 3/4" headers. seat of the pants feel was VERY noticable also. i wish i wouldn't have sold my old 2" super comps, i'd send them to Robert and he could see for himself on the car at the track, like i did. peace, fellas.

"Motor Martyr," you may not believe everything you read, but I don't get the impression you've read my story. It would seem you've chosen to believe only what's been (sometimes erroneously)posted on this board about it.

Let me know what tests you'd like to see full numbers on and I'll post them. I only have time to type in two or three.

DF

post the information i requested, thats all.

The info you requested is irrelevant to the nature of the story, which you'd know if you had read it. Our stated intent was to show the average street guy what he could expect with the most common off-the-shelf headers, not what the hardcore racer could fabricate from scratch.

DF

that information is what makes the difference in power, just as much as the tubing size.

Its disreguarding information like this, that makes for a misunderstanding of what actually made the effective power increase or decrease...as well the change in the RPM band.

The tubing lengths themselves are extremely important to the effective RPM band of the motor, as well the diameter, and the design of the collector.

A much more interesting article, IMO would be finding the difference between Merge collectors, Ed henneman's style of collector, the Tri-y (a real tri-y) collector, and the Flowmaster scavenger collector (Similar to the Tri-Y).

In a street/strip car that is, not on a dyno.

Read the story.

DF

The problem with reading is much like the problem with talking - people pay attention to what suits them. Two ships passing in the middle of the night.

Maybe we need a new topic area: Freiburger vs Martyr. Of course Freiburger knows that mistakes have been made in test articles just the same as Martyr has benefitted from reading through a great many (insert automotive subject area of choice) articles.

Ah, the details of semantics. On one side is an author reminding all that it was an "off the shelf comparo", and on the other side is the young man who fabricated partial custom headers for his ride. Not quite equivelent.

I say to keep the comparo articles coming, and I hope that Martyr actually tests the criticized parts - otherwise it is just bench racing.

Thomas

You're a wise mediator, my brother. Thanks for the level head.
DF

I just don't like the misinformation that's been passed down through the ages. I had some reputable shops and car builders tell me to build anywhere from 2.25" to 2.5" headers for my BBC S-10 Blazer without even asking me what engine I planned on putting in it. They still give me crap for building 1.75" primaries. My engine is somewhat similar to the engine in the HRM article. My heads don't flow as well, but my cam is a bit bigger. I'm running a Vortec 454 with a ZZ502 cam. After reading the article I second guessed myself, but again they were off the shelf and not custom made. If someone made headers for my application I'd have put anything on there to save myself the 120 hours of fabrication I put into my exhaust.

http://www.wisconsinstreetdominators.com/forum/vbgarage.php?do=getimage&id=77
http://www.wisconsinstreetdominators.com/forum/vbgarage.php?do=getimage&id=79
http://www.wisconsinstreetdominators.com/forum/vbgarage.php?do=getimage&id=83

With respect to your opinion thomas, i'm not critizing the parts, i'm critizing the comparison.

The comparison was between 4 headers of different tubing diameters. Making No mention of the gauge of the tubing used in each one?

You made no measurements on the length of the primary tubes on each cylinder, on the each set of headers.

Are you also comparing unequal length headers to equal lenght?

If they are equal, then how equal are they? Whats the tolerance held on each header?

Did the 1-3/4" headers have a flared opening?

Were the header flanges matched to the port?

Did the collectors (not the extensions) used on each of these headers feature the same deign characteristics, including size, length of transistion and length of the collector?

Reading this article, these are the questions that i ask, that arent answered.

Oh good grief!

Put a few years on Brian and he will be positively intolerable.

Or a very good crew chief or test engineer or something. Of course there will be a problem when he reaches Top Fuel: just where to put the damned collectors :D ???

Seriously, loosen your grip on an article written for the mass market with all its limitations - but hold your thoughts for the SEMA engineering conference or your forthcoming SAE research article.

What you may not yet appreciate is that professional writers always have to keep their target audience in mind. In this case it will do Freiburger no good at all to write about how a certain product should be made or designed or the differences even within a genre of products when there is no "ideal" product awaiting the general enthusiast population. Nope, quick and dirty and unequal just like the average guy. Yes, Freiburger's article is "soft", the hardcore racers will seek out their answers - usually through sources beyond popular magazine rack titles.

The top stocker racers actually achieve their results in much the same way of that header comparo article: over time they try a lot of similar but different parts, only their test of choice is often on the track rather than a dyno.

Thomas

yes, i agree brian, you are not seeing the point here, the point is to show to the average hot rodder/reader which headers that you can buy antyime you want from the parts store will make X power. Yes there could of been more info, and there should of, but you are going way too deep. The article was a simple article to help people who aren't having custom exhaust done which over the counter headers will do with a similar combo. Of course it is done because the over the counter header companies will support it, but so what, most people are buying over the counter headers, so it is usefull to the average hotrodder. I too would love to see a way techincal in depth atricle with professionals testing crazy stuff that you would have to read 3 times over to understand, but the chances of that in a hot rod magazine arent very likely. So try to ask freiburger more reasonable questions that actually aply to the topic.

I really think the larger headers make more overall power usually, but I'm sure some combinations et better with smaller diameter primaries. Vehicle weight, gear ratio, all effect which headers will et the best. Dyno numbers are the only real way to determine what headers actually make the most power. Track time really means nothing unless you tune the whole combination for the changes. 2" primary headers might work good on a light car with deep gears and probably not so good on a heavy car with highway gears even though the engine makes the best power with them installed. Many variables here. The total combination is what determines header size, just common sense. Freiburger, I think it's cool you jumped in.

Dyno numbers are the only real way to determine what headers actually make the most power. Track time really means nothing unless you tune the whole combination for the changes I think you have that backwards, Dyno numbers are bench racing material,most are done in ideal conditions...HP numbers mean nothing,Torque numbers are whats important. Track time is true performance. I still want to see a graph of the header tests :D

I'm sure the top engine builders care nothing about dyno numbers, ya right. Build it for the most power then try and get it to the ground, it's that simple, IMO.

Seems to me like the 'header test' syndrome appears every few years, some magazine grabs a few OTS headers and makes a comparison then everybody jumps to the conclusion that suits their preconceptions. Ed Henniman's site has some interesting observations about these tests as to their real value.
http://www.headersbyed.com/info1.htm

I would ask the same questions Brian is asking - what are the real differences between the headers besides the primary tube diameter? We're dealing with headers designed in the 60's, maybe we should test some headers designed in the last few years.

I'm waiting for the jet test to prove once and for all which jets make more power. A magazine will go out and buy several sets of OTS jets and test them in a mule carburetor and report to the world which ones are better. I think 76's are way better than the 81's.

I see both Brian's point and Freiburger's and take the article for what it's worth, but what is really needed and if HRM is listening is an article on headers for the hardcore " hobby" racer ......we want questions answered that "ED Hennimans brings up on his site and excellent tape .......we can handle the techincal info so hopefully some mag will see the value in reaching some of it's long time readers ....talk to the header mfg like "ED" Jere Stahl .Jack Burns etc etc ...... merge collectors , tri y"s etc etc There is alot of header design stuff going on outr there that the average guy is not aware of and no " Brand name" mfg is marketing anything really different ...... what really surprises me is alot of us spend aton of $$ on our motors but balk at coughing up for a good set of well designed headers opting for the 100.00 specials on a trick motor??

BTW a decent header article in PHR "Engine Masters" Fall edition on headers and sizing ......just enough info to get you thinking

I think we should be glad the test was on a Big Block Chevy, instead of a Honda. :D

Seriously... you spend 4 bucks for a magazine or shell out 20 bucks a year and expect a university study on every theory of header building or expect a top fuel crew chief and a NASCAR crew chief to give you 40 years of racing secrets? Get real... you aren't gonna get that for a lousy 4 bucks. A test that detailed would cost thousands of dollars. Then only about 5% of the readers would even be able to understand it, while the rest would turn the page. Also that comparision would be more like a book rather then a few page article. This is exactly why you pay 1000-1800 dollars for a set of custom race headers. You aren't paying to have a header built... you are paying a builder for what they know and for research they have performed.

In the end I agree that some additional measured data like Motor Martyr asks would be nice info for the more advanced reader. You don't need to explain the differences and all that, but posting the size and numbers on each measurement would be a nice addition and wouldn't take a lot of time to do. It also would give us more educated racers and enthusiasts the information we need to make a more informed decision.

I think the monthly magizine market is seriously lacking an offering for a more advanced racer/enthusiast/builder. The basic newbie articles are getting to be way overdone in every mag. I think the first mag to step up to cater to a more educated group would sell alot of magizines... even if it was just 5-8 pages an issue. I think this is why online forums have become so popular with automotive enthusiast and racers. Look at the information that passes through some of the racer forums or a site like chevy talk. It is way beyond what magazines are writing about and as the traffic of these forums shows... there is a demand for it.

In conclusion the article I thought did a good job of doing some comparisons of off the shelf headers and of educating the newbie enthusiast. The newbie reader is smarter most likely after reading it then before, but it leaves some voids for the more educated enthusiast.

When they can write an article to pass muster by all you " Central Scrutinizers", it'll be a better world! tongue.gif

i could, but they dont even try.