are headers worth it? - Team Camaro Tech
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post #1 of 15 (permalink) Old Apr 3rd, 03, 12:15 PM Thread Starter
 
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I have a '69 with a goodwrench 350 and a 4 speed that i will be driving on a daily basis around town, and I am now saving my money to start modifying my engine, as that is about the only thing I have not changed, save for an edelbrock rpm intake and a k&n filter.my current plans for the motor are to switch out the heads with 23* trick flows and change the cam to an xe268. my exhaust is currently dual 2 1/2" pipes with flowmasters and stock manifolds. my question is, given that this is a daily driven vehicle with power steering, power brakes, and vintage air, A) would i be able to fit headers, and B) would it cause enough of a difference in performance to make it worth it? the only reason i even ask is that i have heard so many horror stories about headers like they wont fit right with all the accessories, they always come loose, they blow gaskets, etc... i have had people recommend shorty headers, but i have no idea how these perform compared to full headers.
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post #2 of 15 (permalink) Old Apr 3rd, 03, 12:48 PM
 
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Yes I think it would be worth it.

You might want to consider Doug Thorly's "Tri-Y" headers. I am pretty sure that they will compliment AC and other accessories.

The nice thing about Doug's "Tri-Y" design, is that it provides across a wider RPM bandwidth that that of most other equal length headers. They will also provide more ground clearence than most other headers out there.

As for bolts coming loose, my experience shows that after the initial heat soak they will need to be retorqued. At this time it is a good idea to used some teflon tread tape to put around the threads, reinstall and torque. This takes care of them backing out.....

As for gaskets, this is mainly bolt related too. If the bolt comes loose, it will almost always burn the gasket. I use Fel-Pro's steel core construction gaskets (FFP-1406, 'D' port) coat them with copper spray gasket and use teflon on the threads....along with ARP saftey wire bolts. Needless to say, I havent had any problems with leaks for years.

Just my .02C

[ 04-06-2003, 01:12 PM: Message edited by: chicane67 ]
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post #3 of 15 (permalink) Old Apr 3rd, 03, 12:51 PM
 
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Yes and NO
I like header and my friend Gary hates them with a pasion for the reason you said.
I get the best header I can aford,Headmans.
and Gary ports out his stock headers. and runs
On his side you can get to the spark pluges a hole lot better
Larry [img]smile.gif[/img]
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post #4 of 15 (permalink) Old Apr 3rd, 03, 07:42 PM
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On a '67 and with two set of headers, I had problems clearing the power steering, shift linkage, factory AC, Spark plugs, and with ground clearance. Looking back I would have been a lot better off using ported manifolds...

*But* with headers that fit past the power steering (I have heard dynomax fits), no AC, better access to my plugs (angle plug heads perhaps?), manual trans or floor shift, and a higher stance, I would definitely try it again.

Basically what I'm saying is plan your setup well. There are a lot of variables that tech phone reps can't assist with...

If I knew then what I know now...

Ethan '67 327.
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post #5 of 15 (permalink) Old Apr 4th, 03, 06:04 AM
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I've always had good luck with headers. However, I believe 'luck' has nothing to do with it. Here's what you need:
1. Good quality headers (thick flanges)
2. Good quality gaskets (collector and flange)
3. Good quality fasteners and retorque after a couple of heat cycles

That's really all you need. People usually leave out one of those points and hate headers from then on.

Matt Jones
Lead Mechanical Engineer
Art Morrison Ent. Inc.
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post #6 of 15 (permalink) Old Apr 4th, 03, 06:54 AM
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Paul
 
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I have headers on my 69 and they have caused several problems including clearance issues, burning plug wires, higher engine compartment temps, etc.

How much do cheapo small tube headers give you over the stock manifolds? I like the fit of the stock manifolds, but headers have always been marketed as giving BIG HP/TQ gains....What's the real bottom line here....10HP, 50HP?

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post #7 of 15 (permalink) Old Apr 4th, 03, 09:33 AM
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I have wondered how much HP gain as well. I have read various numbers, but my question would be what is the gain of ported cast manifolds vs. headers. If you gain 20 hp with headers and 15 with the ported cast pieces I think you go cast, but if it is much higher (differential) then maybe you go the header route. Does anyone know this differential?
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post #8 of 15 (permalink) Old Apr 4th, 03, 09:44 AM
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Matt Jones
 
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Well, it all depends on the rest of the system.

If the rest of the exhaust is choked up, then headers won't be as effective (but they still will be). If you've got a big cam with lots of overlap, then the lack of exhaust discharge abilities will contaminate the incoming air/fuel mixture...not good.

Bottom line is, headers make more power than stock cast manifolds probably 90-95% of the time. Even if you port the old Corvette manifolds (with 2.5" outlet) like crazy, headers will still make more torque due to the tube length. Cheapo headers tend to make just as much power as more expensive units; the designs are the same (mostly), but the expensive header is of better quality.

Follow the advice I gave above. If you're burning plug wires and boots, get some protective sleeving (I did this also, look at my webpage).

The more radical the motor, the more power you are losing with manifolds.

Matt Jones
Lead Mechanical Engineer
Art Morrison Ent. Inc.
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post #9 of 15 (permalink) Old Apr 4th, 03, 11:10 AM
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If you don't install headers your heads/cam mod will be a complete waste of time - why would you spend money to make your engine breathe better only to constrict it at the exhaust? I installed Doug Thorley tri-y's (Summit $329) on my '69 (vintage air, P/S, auto) and have never had a problem with them, and yes you will have to re-torque them a couple of times after heat-cycling (per directions). There is no money to be saved by buying cheap headers - you do get what you pay for. If your friend hates headers he more than likely has selected the "cheap road".
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post #10 of 15 (permalink) Old Apr 4th, 03, 12:53 PM
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Jim
 
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if money is an issue, and i'm sure it is for most of us on camaros.net, why not just use your stock exhaust manifolds until you save up enough money to pick up a good set of headers. That'll give you plenty of time to figure out what you need for your setup (accessories, clearance, coatings). Also, this is the reason i'm not getting headers for my 327 with a 282s cam, when you eventually install headers, you will be able to experience first hand, how much more performace you are gaining. And maybe after, you will have a true opinion about why or why not to install headers with experience to back it up.

1968 Coupe, 327ci basketcase project
1986 Chevy Stepside, 305ci/300hp
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post #11 of 15 (permalink) Old Apr 4th, 03, 06:12 PM
 
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My old Hookers fit fine!!!

They were on the car back in '81 or '82 when I got her back.. pdq67



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post #12 of 15 (permalink) Old Apr 6th, 03, 11:10 AM
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In my opinion, I believe you need to consider the rpm range your vehicle will operate in. When higher (3000 to 7000 rpm), you will experience improvement but under 3000 rpm, improvement is minimal, if any. I do not recall exactly the lower end of the range. It may start at around 3500 rpm. Someone here may be able to chime in.

Something else to consider, you mention you have Vintage Air, you may need different ac compressor brackets. It seems when I installed Vintage ac for my pickup, Vintage wanted to know if I had headers or original exhaust manifolds. I am not certain, but you may want to contact Vintage to be sure. Or, someone here may be able to tell you.

EricE
68 Butternut Yellow
SS Coupe 396/325
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post #13 of 15 (permalink) Old Apr 6th, 03, 05:34 PM
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Matt Jones
 
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I would disagree. Long tube headers give significant torque gains under 3000RPM.

Matt Jones
Lead Mechanical Engineer
Art Morrison Ent. Inc.
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post #14 of 15 (permalink) Old Apr 6th, 03, 06:31 PM
 
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Yes, small tube, long, four tube headers are good for raising the torque curve below the max. torque point b/c they create good velocity which helps scavage the gases out of the cylinders so they can suck a full chage better.

That's why the little 1.5" headers work fairly good on the 350+ and smaller engines.. And even 1.375" on the littler engines like the 307 and smaller if you can even find them anymore.. pdq67



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post #15 of 15 (permalink) Old Apr 6th, 03, 07:15 PM
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Make sure your A/C brackets will work with headers. Vintage Air asked me specifically if I had headers when they assembled my kit.
Rick
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