Headers?

Blownaway

Registered User
Well it's decision time once again.
I have to decide whether to go with a set of ported factory exaust manifolds or a set of the factory Mustang headers that are supposed to work on our cars with a little modification. (Kooks won't fit into my budget).
Can you guys (or girls) give me the pros and cons of each (if any).
I already have a set of the cast iron jobs ready to be ported, but if I go with the mustang factory headers, what year Mustang will fit my car (95 SC w/automatic 4r70w)?
I plan to finish the job with dual 2 1/4 pipes (with cats) into a Magnunm Perf. resonator and Y out to dual 2 1/4 tail pipes (with mufflers).
Opinions welcomed.:)
 
Headers---
Pro's= Better than the manifolds but then again anything is an improvement over the manifolds.
Con's= Not really tuned right so dont expect them to do anything much more than help the backpressure problem.

Ported manifolds----
Why waste the time and effort theres very little to be gained from grinding out the manifolds. A turd is still a turd no matter how well you dress it up.;)
 
Thanks Mike, point taken.
Looks like the headers get the nod.
What year Mustang has the ones that will work?
 
I dont know which headers to tell you to try. Just do search for headers and several threads will come up.
I didnt want to fool with cuting something up and making it fit.
I built my own headers.;)
 
Does anyone know how much alteration it takes to make the MAC 3.8 headers for the Mustang work for our cars?
 
Look in the for sale section. I'm selling a pair, pics also, including a comparison shot. The 94-95 are the ones you'll need. They flow almost identical to the mac shorties for the same years. The 96 and up were corked down somewhat so I'd stay away from them. You can also use the 96-97 tbird v6 n/a manifolds. They are tubular, header style, and are a direct bolt up. They are also a bit harder to come across. You would probably have good luck finding the tbird n/a manifolds from an auto wrecker/salvage yard.
 
Check out the thread linked below. It's quite a chore to get the tubes to work, especially if you can't do the welding. The problem is with the location of the steering shaft. The thread has good pictures on the extend of the clearance issue.

http://www.sccoa.com/forums/showthread.php?s=&threadid=26062&highlight=mustang+header

If you're not in a hurry you might want to wait a bit and see what Tbird88 comes up with. He's building his own headers and he might be at a point where he'll build some for others for a lower cost than the Kooks and a cost similar to the Mac's but without the extra work needed.

Here is the thread where he is cataloging his efforts:
http://www.sccoa.com/forums/showthread.php?s=&threadid=30094
 
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Ask Dam Sly he just did a set for his car. Seems to me there is welding skill involved.
 
MIKE 38sc said:
Headers---
Pro's= Better than the manifolds but then again anything is an improvement over the manifolds.
Con's= Not really tuned right so dont expect them to do anything much more than help the backpressure problem.


I don't think with our blowers a tuned header will do much for us. Tuned headers use the scavenging effect. With forced induction scavenging doesn't work so much. I think all we need to do is reduce back pressure which a the Mustang headers, manifolds do. If we were going upwards of 7000+ rpms scavenging may help but even with my big cam the engine rarely gets up to 6000 rpms.
 
i just put the mac headers on my 35th anniversary and they were not easy to adapt. the passanger side header goes right on and fits fine, but the driver's side is a little tough. first you have to gring the existing welds on the flange, then you have to rotate the flange 90 degrees and re-weld it. but you have to be very careful while grinding and welding because they are a very thin metal. then you still have a problem putting on the driver's side header because of the steering shaft, but there's an easy way to put it on. you have to take out the motor mount bolt on that side and use a cherry picker to lift up that side of the motor, then you can drop the end of the header past the steering shaft. then let the motor back down just enough so you can put the header bolts on then drop the motor all the way back in put the motor mount back on then you're almost done. not ice i said almost!! the stock downtubes will not bolt up to these headers, because the headers come down at a different angle than the manifolds and the downtubes are the same size as the collector on the header so you need custom downtubes.


However, if any one wants to buy these headers, you can ship me the driver's side header and i will weld the flange in the right position and ship it back with two custom downtubes for 100$. It's a lot cheaper than an exhaust shop will charge.

any questions e-mail me at adamrg311@hotmail.com
 
Something I am going to do is use the Mustang tubular exhaust manifolds and cut off the flanges. Then weld on collectors that end up going straight back like a long tube with a flange on them. I am then going to bolt my 3" cats directly to the collectors and run dual 2 1/2 from there. Should be a pretty clean setup and the manifolds only cost me $20 and I bought mandrel bends($40) to make collectors then flanges($20), then bought ceramic coating($10) to spray on when done. All together it will only cost me about $100 for headers. I like the fact that I can run open headers too if I want. May be good for a tenth or two.
 
Aaron Pedroza said:
I don't think with our blowers a tuned header will do much for us. Tuned headers use the scavenging effect. With forced induction scavenging doesn't work so much. I think all we need to do is reduce back pressure which a the Mustang headers, manifolds do. If we were going upwards of 7000+ rpms scavenging may help but even with my big cam the engine rarely gets up to 6000 rpms.
That is a common misconception concerning forced induction motors and exhaust.
Could I ask what youre basing that theory on?:)
 
Without technical terms(because I don't know them), scavenging is basically causing a vacuum from sound waves to draw out the exhaust correct? With VE being 100 at best, except in the rare trick applications, with an NA engine having the exhaust drawn out helps a lot. Well in a SC engine the VE is up to what? at least 150%, how are you going to tune an exhaust to help draw it out faster than the pressure the SC is forceing it out? Basically from what I have read is to just have it big enough to accept everything that is being thrown at it. Also when you are looking at supercharged engines in drag racing,when conditions allow, then exhaust for blown motors are pretty much always straight header pipes, no tuning there, just getting it out. Now I could be wrong but it all makes sense to me.
 
OK Aaron I see what your line of thinking is now.
The sonic waves are doing more than 1 thing. True the sonic wave is creating neg pressure as it leaves the exhaust valve and starts traveling down the primary tube which greatly helps scavenging of the cylinder. But there is something else that takes place when that sonic wave reach's the end of the primary tube and this seems to be where most people get lost.

When the sonic wave reach's the outlet of the primary tube another sonic wave this time posative in nature travels back up the tube to the exhaust valve. This wave helps to reduce the amount of fresh intake charge that is trying to escape the cylinder during valve overlap.
Those zoomie headers you spoke of still use this principal.
You cant really use a top fuel car as evidence that headers dont work on supercharged engines. Those engines are built to go 1/4 mile at a time. Street engines are different animal altogether and alot of the design that goes into them has nothing to do with streetability.
 
Ok, well maybe you can help me decide how long to make the collector. I was just going to bring it down until it was next to the tranny but if there is a good length then I could do that. I know with the primaries actually dumping off while they are angled down it will screw up exact numbers but what kind of collector length should I look at?
 
Sure I could figure out the dimensions for the headers for you but I need to know some things first.
When you talk about modifying some mustang headers. Which headers excactly are you talking about? If you mean the tubular exhaust manifolds that come on the mustang from the factory then forget about it, because you cant tune them.
Nothing with short primary tubes can be tuned properly.
The needed dimensions are just not there to work with.
Here are some qeustions I need answers to in order to give you some good dimensions.
1. What will the car be primarily used for?(street, street & strip or strip only)
2. What RPM range do you want the engine to make good power?
(off idle-5500, 1500-600) These are just examples of the answer, you tell me where you want them to work.:)
 
Ya, I guess I kind of knew that. I am using the factory tubular manifolds. I will just have them dump off where I originally planned. Really the only reason I am doing this is because I have a really bad exhaust leak with my stock manifolds. I bought these a while back and figured "what the he!!" they will be better than stock manifolds and it will make me go to true dual exhaust then. I found a cool site that talks about everything you were saying. Haven't had a chance to read it all yet though.

http://headerdesign.com/extras/design.asp

Maybe one day I'll get a set of these headers and cut them up to use the stubs and make me some headers. $700 for what is offered just seems ridiculous though.
 
I agree Aaron $700 for a set of headers is rediculious.
Thats why I built my own. I have $135 in a set of longtube tuned headers and that includes ceramic coating.
I did all the work myself. Thats why theres only $135 involved in them.;)
 
I'm east of the Mississippi river a long way from you.
That coating you posted looks interesting, I've never heard of it.
The oven thing is a problem for most people. I'm lucky in that area because a buddy of mine has a powdercoat shop and I can get anything powdercoated or baked for free.

I have all the resources to crank out SC headers for a realy good price and offered to do so over a year ago, But response was dismal and there was alot of nay saying going on so I retracted the offer and just satisfied my needs.

Can you gas weld? How about TIG welding?
I could provide you with the proper dimensions and you could just fit the headers up and weld them out yourself and then coat them.:)
 
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