Tuned vs Non Tuned Headers [Archive] - Chevelle Tech

: Tuned vs Non Tuned Headers


66 SS Big Block
Jan 31st, 07, 2:08 PM
Hi Guys,

I read the recent thread on ceramic headers. Considering the responses, I have decided to do the jet hot route. Now for the question. The tech at jet hot said for street use I would not notice a difference between a tuned header and a non tuned. I am not planning on racing so this is for street use and ocassional hot rodding. I am going with 2" primaries with a 3 1/2" collector. Also I am leaning toward the Hooker brand. Super Comp ( which is tuned ) and the Comp. obviously non tuned. Difference in price is 200.00 between the 2. So will I see a 200.00 difference in preformance?

Thanks in Advance.
Frank
66 SS Big Block

CDN SS
Jan 31st, 07, 2:14 PM
Equal Length headers ..... On the street thru the mufflers .NO !!!

2" primary is pretty big do you have a 550hp motor or more ?/ if not go for 1 3/4 to max 1 7/8" primary pipe and I like a 3" collector .the smaller sizes will build velocity / heat and make more torque down low ...... Hedman makes a very nice fitting header on early BB chevelles with 3" collectors ......do a search you will find lots of info on headr sizing .....sizing all based on your engine HP and end use

bracketchev1221
Jan 31st, 07, 3:00 PM
Both headers are somewhat "tuned". I believe the selling point on the super comps was that the tube were within 5% length of each other while the comp headers are 10% length of each other. Will you notice a difference no. Probably an easier fit with the comp headers.

Chris Stanwyck
Jan 31st, 07, 3:15 PM
Good advise from CDN SS.

Motorhead62
Jan 31st, 07, 10:21 PM
Frank,

A set of 1 3/4" primary long tube headers will work just fine for a street car.

I like using DynoMax and Hedman myself. Hookers are way over priced IMO.

Good Luck! :D

66 SS Big Block
Feb 1st, 07, 12:29 AM
Hi Guys,

Thanks for the responses. I will look into it a little more. The car is a 375 Horse with the square port heads. It does have a cam in it so lets say between 375 and 400 althought the 375 in 65 was rated at 425. I had a typo on my intial post. The difference in price is 300.00.

Thanks.
Frank

mr 4 speed
Feb 1st, 07, 9:25 AM
Frank,all you need is 1 3/4" primary 3" collectors for your ride.
You will NOT feel $300 worth of increased performance using anything bigger :D

CDN SS
Feb 1st, 07, 11:23 AM
Hi Guys,

Thanks for the responses. I will look into it a little more. The car is a 375 Horse with the square port heads. It does have a cam in it so lets say between 375 and 400 althought the 375 in 65 was rated at 425. I had a typo on my intial post. The difference in price is 300.00.

Thanks.
Frank


Street 396/375 square port head ....... all the more reason to not go too big, those rect heads dont make a lot of torque down low unless you have 4.10 gears stay at 1 /3/4 max 1 7/8 ...... tuned and equal length are two different things . tuned means just that, tuned to the application and end use . street with street gears you want torque down low in rpm range and also collector sizing is very overlooked in chosing a header ...... tuned for your use and engine is smaller primary like 1 3/4 and collector 3" and if you really anal collector length ....... I like the hedman since they one of few mfg. who make an off the shelf header with 1 3/4 with 3" collector .....suggestion if you want max tune use 3" exhaust pipe from header to muffler then 2 1/2 tailpipes FWIW

engineguy
Feb 1st, 07, 11:27 AM
The term "tuned headers" is a marketing term and is about as outdated and non-descriptive as categorizing cams as "3/4 Race and Full Race".

A "tuned header" usually describes a header that has equal length (or nearly equal length) primary tubes. We all know that primary tube diameter, tube length and collector design all go into the receipe for a tuned header. Now, the chore here is to get the header "tuned" to the RPM at which the engine makes the most horsepower. A "tuned" header is actually in "tune" during a very short RPM band. (This RPM band is even shorter in a high RPM Pro Stock of Competition Eliminator class car.)

In summary - no, a "tuned" header is not at all necessary in a street or street/strip application. This is because a steet or street/strip vehicle needs to produce HP and torque throughout a wide RPM band, therefore the header would be in "tune" for a very minimum amount of time.

GRN69CHV
Feb 1st, 07, 11:32 AM
I run 1.75" X 3" Hedmans on a 10.3/1 233/236 .600/.610 lift hyd roller cammed ZZ454 motor. This motor hits harder at 3000 - 6000 RPM than any other motor combo I have ran. No question about it, the smaller tubes yield throttle response. Bought these when the car had a 396 motor and decided t give them a try with the bigger motor, glad I stayed smaller. With a 460CI motor, most likely would like a 2" x 3.5" for more power the other side of 6000. If it were me , a rec port 396 motor would get a full divided plenum intake and 1.75 primaries.

grovey
Feb 1st, 07, 8:56 PM
i used the hedman 1 3/4 x 3" in the painted version. i have raised port heads on mine. they fit ,but not good here a dent ,there a dent . also i ruined a pair of hedmans with 2 " primarys trying to make them fit. both sets were ( for my car). junk imo. my buddy used hooker comps with 2 ' x 3 1/2 " and they fit his 66 great ! did i say , yes i said great !

66 SS Big Block
Feb 3rd, 07, 12:45 AM
Hello Everyone,

Thanks again for the good responses. I picked up a summit book @ work and I noticed that most if not all header companies smallest primary tube for a 396 is the 2 by 3 1/2. I even called summit and the tech guy confirmed it. I did call Comp cams and talked to the guy that helped me pick out the cam I am currently running. I explained my operating conditions and what exhaust I am going to run. The cam has a rpm range from 1600 - 6000. He recommended a 2 by 3 1/2. So now I guess it is going to be preference?

Thanks Again,
Frank

CDN SS
Feb 3rd, 07, 11:24 AM
Hmmmm , lets see advice from lots of experienced BB folks here ..or advice from order taker at Summit and Comp !! What to do ??

cuisinartvette
Feb 3rd, 07, 12:25 PM
Ill never buy a "tuned " header again, too much of a pain as far as getting starter in, etc. If I could have bought a nontuned header in the same primary size I would have, they are much easier to install.

66 SS Big Block
Feb 3rd, 07, 12:50 PM
CDN,

I just posted what I found looking for a 1 3/4" primary. After not finding them readily availible I contact summit since they have ALL of the different headers listings, some of which are NOT in the catalog. The tech guy @ Comp was very helpfull and knew his stuff when consulting him on a Cam for the car. The guy that did the cam swap for me races weekly in the summer and he also reccomended 2" primary. So I am not trying to say that you guys don't know your stuff. I am merely posting what I found.

Frank

Frank

mr 4 speed
Feb 3rd, 07, 1:03 PM
Frank,I am not sure about the availability of 1 3/4" primary,3" collectors for 66-67 big block Chevelles.
But I will stress you do not need anything bigger.Its one thing if nothing else is available except for 2" primary,3.5" collector.

Just an FYI,a fellow TCer a few years back had an orange 69 SS396 (his name is Alan,I don't recall his user name but I remember the car and that he was from CA)..similar type 375 HP 396 with an Isky solid cam..he picked ET and MPH swapping out the 2" headers for 1 3/4" headers.

hoffbug
Feb 3rd, 07, 1:25 PM
and if you really anal collector length .......

This thread is too funny!

What is anal collector length? Those would be a little too small IMO :D

77 cruiser
Feb 3rd, 07, 2:34 PM
Look here.

http://www.hedman.com/pages/hedders/pass-chevy.html#chevelle

GuysMonteSS
Feb 4th, 07, 10:38 AM
My rectangular port LS-6 454 came with a set of 1 3/4 inch 3 in collector headers when I bought it,not 100 % sure what brand but I think they are BlackJacks.I've not tried a bigger set for comparison,but with a healthy solid roller cam it sure seems to pull good at lower RPM's.From what I've read I wouldnt go to the 2 inch size unless I had a whole lot more cubic inches or was going racing.

66 SS Big Block
Feb 4th, 07, 4:08 PM
Hi Guys,

Thanks for more good responses. I am going with the 1 3/4 to 3 collector. As far as availiblity goes I don't have many choices for the 1 3/4 to 3 header. Headman and Hooker SC are the only 2 big names. It seems like most manufactures make the BB header in the 2 to 3 1/2 size for what reason I do not know? I really don't want to spend any more than I have too, but I want a header that is going to fit right. I am a little leary about the Headman for 2 reason's. 1: The Headman only has a 1/4 flange compared to the 5/16 on the Hooker. And now for the BIG reason. 1 of the 1st responses to this thread Grovey posted that he had a set of 1 3/4 by 3 collector on his 66 and it didn't fit well. In fact he had to put a few dents in it to get them to fit. Now he did have I believe he said raised port heads? I have no idea how that would effect the fit. He also stated the Hooker fit great. So that leaves me biting the bullet with the Hooker SC. Unless if someone can confirm the fit of the Headman's?

Thanks.
Frank
66 SS Big Block