turtle twerp
New member
Is there any performance advantage of a late model 80's exhaust manifold?
All Small Six Late model exhaust manifolds
- Thread starter turtle twerp
- Start date
This relates to all small sixes
Yes there is they will actually flow much better than any of the other stock Ford 200 / 250 Six Exhaust Manifolds and if you want they can also be converted into a duel exhaust setup very easy by using the the gutted out Convertor Can.
turtle twerp
New member
Thanks Bubba. I was looking at options for better exhaust flow for my 1970 tri-carb Mustang convertible and thought this might be and option to a header and not have to deal wilt starter clearance and a little quieter. Is it difficult to gut the catalytic converter?
It unbolts from the exhaust manifold so that the larger opening will give you all the access you need to knock it out. Our long time site member "xctasy" did a post quite awhile back (it was on December 18, 2015) on how to use these 1980's Exhaust Manifolds for a Big Single or a Duel exhaust system so you can search for that info if you want If I remember correctly the cat is about 4 1/4 inch dia. so you could do a single 3 or 2 1/2 system easy or a pair of 2 inch or maybe up to a pair of a 2 1/4 for a duel system. I think these exhaust Manifolds could also be the basis of a inexpensive Turbo J Pipe hook up too. Good luck
turtle twerp
New member
I did purchase a late model exhaust manifold and read xctasy’s write up about converting it to a duel exhaust (very informative and well written) but for simplicity was going to just keep mine a single. My question is when I have the muffler shop make a plate should I have them reduce it down to 2 1/2” right at the manifold or have them make it 3 or 3 1/2” run a 8 to 10” pipe and reduce it to 2 1/2” the rest of the way back?
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The best way is to have a gentle transition down by tapering it rather then having a flat plate with a 2 1/2inch pipe coming out of the center of it this would probably cause a very Turbulent Area for the Exhaust Flow right there. If you had the stock convertor to gut out that would be the most ideal way. A good second alternative would be finding a Header Collector Hook Up that's matches up closely to the same ID size of the Exhaust Manifolds opening. If I remember right its supposed to be about a 4 1/4 inch diameter and looks like it in your above picture but I haven't measured one of them to know for sure. A 3 1/2 to 4 inch Header Collector that tappers down into a 2 1/2 inch, some of these Collector Hook Up's are a fairly common size like say the 3 1/2 tapering down to 2 1/2 inch ones if that's the size for the Exhaust Pipe System you plan to run, then next you can use a 2 1/2 inch Mandrel Bend of the correct angle needed to get it under the cars floor. Best of luck
1981 Capri
Active member
Turtle good picture , thanks . Bubba , great info thanks , This is the same issue we have ! this is our exhaust question ! do i tag on to this thread or start a new one ? Our 1981 engine is a 200 cid has the original exhaust manifold and the pre light off cat still attached to the manifold . how do i find the write up by xctasy ?
Hi 1981 Capri, it is usually always better to start your own new thread but in this case it might be ok since its about the exact same issues and this was a very recent posting. On finding the older posts we do have a search feature Tab you can use its in the upper Far Right Hand Corner of the Tool Bar, it does help if you know the OP Author of the post your looking for and the general time frame of when it was made too. Sadly the search used to work really good before but not quite as good lately but improvements are being made. To help get you started in using the search functions here is the link to "xctasy's" famous post that was first made back in (Dec. 18, 2015) on how to use these stock late Exhaust Manifolds for a basis of building a big single or a Duel Exhaust system. Best of luck. https://fordsix.com/threads/chad-stock-factory-4-1-4-eobe-9430-ke-header.74163/
turtle twerp
New member
I just typed in late model exhaust manifold in the search in small six and xctasy's post came up about halfway down the first page and would definitely recommend reading it if you are using this exhaust manifold!
1981 Capri
Active member
Turtle , I would have never found the write up by xctasy based on the thread topic . I find it very intertesting that you would remove what you have to install the exhaust manifold in the picture you posted above . Do you also have the pre light off cat / can that mounts to this exhaust manifold ?
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I doubt famous would be a word I use. More Notorious, Nefarious, or self promoting oriffi.
Whatever, if you use the XCTASY or xctasy wildcard in your Google or FordSix search engine, it will most likely show you all sorts of weird stuff.
I'm an engineer so I ask engineering related questions, and post engineering related responses.
The Stock Factory 4-1/4" EOBE 9430 KE iron header on 250 engines for 1980, and 200 sixes from 1980-1983 had for some time an available EO approved primary light off catalyst, with a giant 4-1/8 inch hole necked down by a stainless plate and a common other converter TIG welded in. There was a an approved number for it.
If , um, "converting" a big 4-1/4" header to a 2-1/4 down pipe, just as Bubba says, try and be smooth in your 4 bolt plate to two lug transition.
The lion's share of the 4 plus inches is not used for port flow, it's there to allow a fine 200 micron mesh coated with a catalyst to operate as an oxidation catalyst.
IIRC, the OEM Primary Light off cat does not have noble metals of platinum and palladium, nor is it rhodium. It's another kind which is why the cross sectional area is so huge.
The guaze type catalyst is very inefficient, so Ford decided to increase the diameter of the exhaust manifold so the catalyst wouldn't reduced horsepower.
The small performance boost in Emissions engines from this was 6 HP, as the log intake runner is no longer heated by a thermatic flap like earlier versions.
Whatever, if you use the XCTASY or xctasy wildcard in your Google or FordSix search engine, it will most likely show you all sorts of weird stuff.
I'm an engineer so I ask engineering related questions, and post engineering related responses.
The Stock Factory 4-1/4" EOBE 9430 KE iron header on 250 engines for 1980, and 200 sixes from 1980-1983 had for some time an available EO approved primary light off catalyst, with a giant 4-1/8 inch hole necked down by a stainless plate and a common other converter TIG welded in. There was a an approved number for it.
If , um, "converting" a big 4-1/4" header to a 2-1/4 down pipe, just as Bubba says, try and be smooth in your 4 bolt plate to two lug transition.
The lion's share of the 4 plus inches is not used for port flow, it's there to allow a fine 200 micron mesh coated with a catalyst to operate as an oxidation catalyst.
IIRC, the OEM Primary Light off cat does not have noble metals of platinum and palladium, nor is it rhodium. It's another kind which is why the cross sectional area is so huge.
The guaze type catalyst is very inefficient, so Ford decided to increase the diameter of the exhaust manifold so the catalyst wouldn't reduced horsepower.
The small performance boost in Emissions engines from this was 6 HP, as the log intake runner is no longer heated by a thermatic flap like earlier versions.
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See "http://vb.foureyedpride.com/showthread.php?185006-3-3-Fuel-Economy-Woes"
Post #17, E1BE-211 is the OEM primary light off cat Ford reference number, replacement is CatCo, #66991
Article gives the size of the cat, and a rough idea of how you might make a single out 2-1/4 inch Exhaust tube....if you use your imagination.
Post #17, E1BE-211 is the OEM primary light off cat Ford reference number, replacement is CatCo, #66991
Article gives the size of the cat, and a rough idea of how you might make a single out 2-1/4 inch Exhaust tube....if you use your imagination.
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