EXHAUSTING QUESTION

[66Sprinter]

Hey, we took our car out for the club cruise this weekend. Over 20 cars showed and drove to dealer for a promo/meet. I met and talked with a guy who had built more than four 250's for oval racing. When I mentioned headers, he just laughed and said that I was stuck in the mud trying to get the dual exhaust look and sound. "In reality, if you just use any 250 exhaust manifold w/flange, yu wil get the performance same as with headers' but you never get the sound!....Oouch!!!

So now my questions...really..the 250 and headers are the same?
Does any 250 exhaust manifold fit any 200? I was humbled by all the big blocks stuck in all the bonnets....only 2 sixes in the meet with mine at least having some chrome on it.

 

[Poney102]

I just put a 6-2 header on my car with true dual exhaust and it sure sounds good to me maybe not like a v-8 but still it sounds strong and the car runs great.

Dave

 

[CZLN6]

Howdy jammer:

IMHO and from direct before-and-after experience- the Headers and 200/250 manifold are not the same. I went from a modified 250 exhaust, on my much modified 250, to a Clifford 6>1 header, with a 2" exhaust system with a DynoMax muffler on both. A port divider was in place for both. I immediately noticed that the idle rpm had increased, it reved more easily, better throttle response and reved more quickly from 3 to 5 grand. I did not quantify the before and after difference, but I try to be realistic and objective and there were several positive differences.

200 and 250 exhaust manifolds appear to be identical. All are interchangeable. All that I've seen and been able to measure are very similar with a few exceptions. Those exceptions are related to cast bungs for air injection and/or EGR fittings. While those bungs do add volume they, most likely, disrupt flow. All had a 2" outlet and roughly the same inside volume.

I have heard of a different exhaust manifold on 250s in Econolines, but have never seen one or found a listing in catalogs.

Any late model 200/250 exhaust manifold can be improved on slightly by port matching the cylinder windows and by grinding and smoothing the 2" outlet to a full 2". But they will never equal headers with individual runners.

That's my two cents. If anyone has or can verify a different and unique 250 exhaust manifold manifold I would very much appreciate the information.

Adios, David

 

[MustangSix]

The only discernalble differnce that I've seen is in the diameter of the exhaust pipe. Early 200's had a 2" headpipe, and the later ones were 2 1/8", I think. The donut is larger and the connector is bigger so they don't interchange.

But that wouldn't make much of a difference in performance.

 

[66Sprinter]

I appreciate your comments. I was probably feeling hurt while the V8 guys took shots at me. To the point, I am trying to save $$ for the headers and hope to put them on without removing the head. I dont really have any engine issues and its seems dumb to remove the head just to put in a divider. If there really was no difference then so be it. However, in this forum there are lots of people with years of experience and I found my self being swayed by a V8 guru who use to race sixes. So on to another dumb question...Why not weld a divider on the header and then install it into the siamese port?

 

[falcon fanatic]

Wow Jammer, that's a great question. I imagine it would be difficult to nail the alighnment but I'll bet you could do that with some good planning. If it works it's a great solution to a common problem. I wonder how to get a good gasket seal, though...

 

[Anlushac11]

Am I missing something here?

If I read this correctly the guy is saying that a tubular header offers no better performance than a stock 250 exhaust manifold on a 200?

Is this post talking about the sound or overall engine performance?

If were only talking about the sound thats one thing but I cant believe the guy would say that the factory cast iron exhaust manifold flows better than a tubular header.

 

[addo]

The "dividing headers" were used here in race classes that did not permit port modifications to siamesed engines. It was considered part of the exhaust system. FWIW, Minis pull AMAZING power with full siamesed heads.

Adam.

 

[66Sprinter]

Yeah...the guy was talking about manifolds vs tube headers...I guess he wanted to bully a 6cyl in front of his buds...

Adam...do recall how the divider was attached..or have acess to any pics...or know where to get them... I want to push this a little further and ask what type of material would I get for the divider and what might be the best weld technique... Once done I coud always use the grinder to give me the best fit, then go ahead and gasket-seal and go.

 

[addo]

Jim, I don't have pics but this was a well-enough known lurk on the 9-port GM sixes. It's my guess they ran 3/8 or so steel plate, ground to shape before tacking on.

Australians generally say "how do you make that" as opposed to "where do you buy it"... I'm not trying to be unhelpful, just to show a different mindset. Anything you fab up that gets in there and stays is progress.

Adam.

 

[66Sprinter]

Ok...thanks..not sure what your point was with the Aussie thing...but I intended to fab it anyways...just looking to see if somebody already invented it...

This American always believes that the more research you do..the more you learn what you dont know..and the higher probability that you will get it right the first time.

Headers is the next awesome thing for my stang...and I am working O/T now for a set from Mike...(havent told him yet though)

 

[addo]

I was referring to the general lack of aftermarket parts for Australian engines, compared to the US. We've been forced into resourcefulness in the past.

 

[66Sprinter]

I truly understand....that can be the reason why the Bros Guru in Idaho do the things they do....being so far from the center of the automotive world.......thats prolly why the internet and this forum are so popular! Thanks so much for your advice. I truly do appreciate it...

 

[Anonymous]

Theoretically I cant see any way that a normal 250 exhaust manifold will allow for the HP increase of a header. Not unless the original is that good that it looks something like a header with all the pipes joining at precisely the right possition.
Talked to a guy who has built many race 250 crossflows. He tells me that bigger primaries on a header will make a significant difference in HP.
Remmember headers work better at freeing up restriction when it is at it greatest (not when there is hardly any, "normal driving") so the effects would be most noticable when youre going "hell for leather."
As far as sound goes I once owned a 1983 Toyota Corrolla panel van with a 1.3 litre engine. The previous owner had put a 2 1/2 exhaust on it. Ridiculuosly large for that car. It had a standard cast manifold.
That car had an "awesome deep throbbing note". people would not believe that it wasnt a worked V8 or something with big HP. I added some headers latter and it made (as far as I can tell) no difference at all to the sound.
I reckon sound is almost all in the exhaust and the performance from the header.
I still havent bothered with a port divider on my 2V. I just cant see how its going to make that much difference. I made the centre division that attatches to the siamese ports on my header between the pipes knife edged at 45 degrees so that it did not act like a wall for the turbulance. I didnt want to risk cracking the head by welding anything to it. Attaching the divider to the headers sounds like a good idea.

 

[66Sprinter]

Hey Tim, thats exactly my point...both sound and exhaust performance. I like the idea of putting a tapered gusset on each side of the divider to help direct the exhaust pressure. Sounds like you already made a divider..but I cant tell if you put it on the header or the head.....could you please elaborate a little more about your mod for the siamese port?

 

[66Sprint6]

Clifford performance makes a divider for like $14 give or take a few. I am still waiting for my header to come in from them, but since it took so long they said they would give me a hat and ceramic coat them for free!! The hats kool and all, but the coating is $100 extra I dont have to pay. Anyways, look online at Cliffordperformance.com and you will find a divider. All of their headers come with the divider and it welds into the block.
Matt

 

[Anonymous]

I didnt actually use a divider at all. The problem as far as a can see is maybe to much volume with two ports joined which a divider would resolve but also the middle flat peice between the two pipes on the header would stire up turbulence and not alow it to escape properly unless a divider is inserted or if the flat peice were tapered back on a 45 degree angle.
This is all I thought was necessary to assist the gas out. Maybe better with divider but Im not going risk welding mine. Maybe I will weld divider to header some time latter.

 

[66Sprinter]

OK...I understand...so you are running headers with no divider. Did you have any problems with the gaskets blowing out...or did you take some extra care in assembly? It would be nice to buy a used 200 head and play around with the flange of the header to see what can be done. If there was a mod to the header flange instead of to the head alot more of us could go straight to headers without the headmod and fear of weld damage.

 

[addo]

It's worth noting that the factory didn't bother to split the 2V port, but did fabricate a couple of different headers (depending on application) - not exactly a cheapskate option compared to casting a specific exhaust - BUT:

The 2V centre ports are lesser in height than on the log heads; more equal to the other four slots. The GMs never had that to begin with. Taking the Clifford divider and making it a snug fit, then fixing to the header could be an option, as it reduces the port height, too.

Possibly the more direct flow of gases on the 2V is a reason for flange face longevity, but they do blow/wear. The s***house exhaust gaskets some places sell don't help either and neither does using a log head gasket on the 2V ports. Both are common enough offences.

Adam.