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Exhaust Manifolds or Exhaust Headers? Go!


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OK folks, let's take a poll. Which is better Headers or Manifolds? I know Headers allow for higher HP, but there must be some benefit to having the functionality of the manifold with the pre-heater shroud attached, right? What do you think? What's your preference and why?

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Prefer the added power of the headers. Theoretically, the preheater just helps the car warm up faster, but I see it only functional if driven in the cold winter months.

Edited by tony-muscle
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20160929_171923_edit2_small.jpg

 

1971 M-Code Mach 1 w/Ram Air, 408 stroker, 285/291 0.558" roller cam, Blue Thunder intake, TKO600, Hooker headers with electric cut-offs, FiTech EFI w/ RobBMC PowerSurge pump

Strange center section with Truetrac, 3.5 gear and 31 spline axles, 4-wheel disc brakes

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The pre-heat shroud is there to supply a warm air source for the factory closed air cleaner system. The air cleaners are calibrated to maintain inlet air temps in the 100°F range, where carburetors will atomize the fuel better. This also provides a more stable inlet air temp, which helps keep performance consistent in changing conditions. If you're running an open element air cleaner, then a shroud is not going to do anything for you. 

I'm a header guy, and mainly because the manifolds are restrictive. 

 

 

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My opinion is it depends on what other modifications (if any) have been made to the engine and what one's goals are.

If you are running a stock-ish engine then I don't think the expense and install time is justified.

But, if the breathing on the intake side has been improved then the OE manifolds are going to be limiting air flow out of the engine.

It is also possible to choose the wrong header- a 2" primary header is way overkill for most street engines...

Headers will deteriorate faster than manifolds, hang lower, interfere with more other stuff in the engine bay and are noisier.

Depends on what else is done to the engine.

Edited by mjlan
Grammar
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Matt

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Headers generally also improve low end torque, due to reducing exhaust reversion, and if sized correctly.

The reasons for cast iron manifolds from the factory include cost, ease of installation, longevity, and are quieter.

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“If you can't explain it simply, you don't understand it well enough.”

--Albert Einstein

 

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It depends on what your preferred use for the car is. I drive mine a ton and don't want the added heat, maintenance and noise of a header so it's manifolds for me. 

I'm also not sure how much benefit off the shelf headers are when coupled with a full exhaust system that has any level of sound control. Sound control tends to equal back pressure. 

Headers will undoubtedly make power when well designed and free to flow, to get the best performance they need to be custom made to suit your combination and chassis. 

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[align=left]Jeff T.

 

When I die I want to die like grandpa, peacefully in my sleep... not screaming, like his passengers. [/align]

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Exhaust manifolds for this cat. 
 

My opinion is admittedly very subjective.  I like driver cars and headers have caused me too many headaches in the past.  To be fair, I’ve never sprung for really nice ceramic-coated ones (though the ones I used were not cheapo ones either) so they quickly became rusty eyesores that kicked off too much heat and noise. Great on a dyno I guess - and the track of course - but I found they can easily rob the low end if not set up correctly... I just prefer the manifolds as a result. 

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Lazarus

 

9-C51-EEB4-A25-A-4-F27-8-D01-0-EB879931296.jpg

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71 M code. Had nothing, purchased headers installed and found the stock ports of the head larger than the inlet of the 4V headers. Actually gave them to the scrap guy and months later scored a pair of manifolds and never looked back.

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You can machine the outlets of the manifolds to 2 1/4" ID, like Ford did on the Boss 351. That's about it unless you send them out for ExtrudeHoneing or spend a bunch of time with a grinder. 

FWIW, the Hooker 6915 that fit the 71-73s are the easiest header I've ever installed, and I've had multiple sets. The new set that I recently bought fit without any issues at all, they bolted right up. Unfortunately, they are now made in China, but the ports now match the heads, the bends are better and the welding was very good. They switched to a flat head flange from the welded sealing flanges, and it sealed up without any sealer, just a Felpro header gasket. 

HOOKERCOMP.JPG

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9 hours ago, Hemikiller said:

You can machine the outlets of the manifolds to 2 1/4" ID, like Ford did on the Boss 351. That's about it unless you send them out for ExtrudeHoneing or spend a bunch of time with a grinder. 

 

Interesting. If the Boss 351 made 330 HP through manifolds, maybe it's worth looking at increasing the outlet to 2.25" ID.

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I will be going to stock on my next 73 and I will be running manifolds for quiet operation and ease of install for factory exhaust. My 71 has headers and it gets very warm under the hood!

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Interesting responses here. I've heard a couple people mention easier maintenance with Manifolds. What kind of maintenance needs to be done with headers?

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1 hour ago, Murdoc said:

Interesting responses here. I've heard a couple people mention easier maintenance with Manifolds. What kind of maintenance needs to be done with headers?

In my experience, header bolts continually loosen and gaskets fail. They need continual maintenance if you want them to look nice. I've never had a set of manifolds rust through. 

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[align=left]Jeff T.

 

When I die I want to die like grandpa, peacefully in my sleep... not screaming, like his passengers. [/align]

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Headers for me. I am one of those guys who thinks that way too much power is just right. Less restrictive, more mid-range torque, more upper RPM power. You must have then coated, preferably inside as well as outside, if you want them to last and reduce under hood temperatures. If a quality gasket is used, and a THIN coat of the RTV of your choice is applied to both sides, installed, and let cure completely (24 hours) they won't leak and they won't burn out. A split or toothed lock washer will keep the bolts retained.

Chuck

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The bolts loosening are the biggest headache, but there are locking fasteners available, which are their own headache installing them, one example:

FORD Stage 8 Locking Fasteners 8912A Stage 8 Locking Header Fastener Kits | Summit Racing

Headers, and exhaust systems, aren't as prone to rusting out as they were when we had leaded gasoline, so rust isn't the problem it once was. The chlorides and carbon in tetraethyl lead additives combined with water vapor to form mild acids in the exhaust, causing rusting from the inside. Using exhaust wrap to insulate and quiet headers can hold moisture and cause rusting from the outside.

Parking lot speed bumps aren't kind to low hanging headers.

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“If you can't explain it simply, you don't understand it well enough.”

--Albert Einstein

 

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I have ceramic coated Hooker headers and haven't had an issue with the bolt loosening. May not be related to the coating at all, but tightened the bolts during installation and retightened them afterwards.

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20160929_171923_edit2_small.jpg

 

1971 M-Code Mach 1 w/Ram Air, 408 stroker, 285/291 0.558" roller cam, Blue Thunder intake, TKO600, Hooker headers with electric cut-offs, FiTech EFI w/ RobBMC PowerSurge pump

Strange center section with Truetrac, 3.5 gear and 31 spline axles, 4-wheel disc brakes

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16 hours ago, Hemikiller said:

You can machine the outlets of the manifolds to 2 1/4" ID, like Ford did on the Boss 351. That's about it unless you send them out for ExtrudeHoneing or spend a bunch of time with a grinder. 

FWIW, the Hooker 6915 that fit the 71-73s are the easiest header I've ever installed, and I've had multiple sets. The new set that I recently bought fit without any issues at all, they bolted right up. Unfortunately, they are now made in China, but the ports now match the heads, the bends are better and the welding was very good. They switched to a flat head flange from the welded sealing flanges, and it sealed up without any sealer, just a Felpro header gasket. 

HOOKERCOMP.JPG

I am very curious about this. You say that the ports now match, how recent did they make this changes?

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20160929_171923_edit2_small.jpg

 

1971 M-Code Mach 1 w/Ram Air, 408 stroker, 285/291 0.558" roller cam, Blue Thunder intake, TKO600, Hooker headers with electric cut-offs, FiTech EFI w/ RobBMC PowerSurge pump

Strange center section with Truetrac, 3.5 gear and 31 spline axles, 4-wheel disc brakes

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I've been running the ceramic Hooker headers for quite a few years.  I haven't had to tighten any of the bolts since installing the headers, and with the ceramic coating they still look as good as they did new.  Definitely not the same as the ones we used to get in the 1970s!

I think extrude-honed manifolds would be very nice, too.

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Both of my manifolds had leaks where gasket material had blown out.  I thought about swapping over to headers.  But as others have mentioned, I didn't want to deal with the prospect having to constantly retorque the header bolts.  Instead, I decided to keep the manifolds.  I had a machine shop resurface manifolds so they would mate up true to the heads.  No regrets.

 

 

Jason (71 Mach 1, 351C 4V, 4 Spd. Toploader, Grabber Blue)

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My headers have been on for years with 0 issues and never have to tighten bolts.  I run nice thick copper gaskets.  They are reusable and seal well. 

Kevin
1971 Mach 1

408C Stroker - C4 w/3,000 stall - 8.8" Rear w/3.73's - Disc brakes all way around.

 

 

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1 hour ago, turtle5353 said:

My headers have been on for years with 0 issues and never have to tighten bolts.  I run nice thick copper gaskets.  They are reusable and seal well. 

I have no issues either, but run the fiber composite gaskets. Everything I had with a V8 had headers, and they were used year round. The cops would pull you over for the stupidest things back then, so you learned how to keep the headers sealed up, and it came down to being meticulous with tightening the bolts, and having an exhaust system that didn't swing around in the breeze. My 73 Chevy crew cab dually taught me how to hang an exhaust system so that it didn't eat collector gaskets, as there was about 14ft of tubing to the bumper. 

My go-to for years was the MrGasket white composite gaskets with a coat of UltraCopper on each side. The Hooker gaskets were pretty good too. I once made a set for a friend's Cuda out of the previous night's pizza box....

 

7 hours ago, tony-muscle said:

I am very curious about this. You say that the ports now match, how recent did they make these changes?

I bought my headers in the fall of 2020, took about five months to arrive from Holley. I'm assuming the change was made when they sent Hooker production to China. To be honest, these are a much nicer header than the Mexican made units I bought about ten years ago. 

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If you go headers consider Nord-Lock washers.  They are simple and work.  McMaster-Carr sells them.

https://www.nord-lock.com/nord-lock/products/washers/

 

I have Sanderson shorty headers on my car (ceramic coated) I don't have more than 300 miles on the car yet, but they are good so far.

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I have the ceramic patriot headers for 2v heads. 0-60 is 5.3 with 2v heads, 213,213 cam, performer intake with 1 inch spacer, holley 600 vac secondary. Oh and factory crank, rods and crappy dished cast pistons. Headers are the best bang for the buck and the combo does not have to be wild in my opinion.

 

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Very simple -- go to my youuut000b 

the red one has long headers -- the green one has original manifolds

 

 

 

I like both -- but feel the plumbier sound of the green sportyroof is more exciting

 

Edited by 1sostatic
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Enjoy's searching out 71-73 history

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