Hey guys,

This might not be important for many people, but it is important for me - and might be helpful for someone down the road.

I want to re-create the shroud which surrounds part of the exhaust, where the exhaust manifold connects to the exhaust pipe. It is connected via one bolt to the bottom of the exhaust manifold, directly under the carb/EGR/intake stack. This shroud is connected via flexible "tube" to the bottom of the air-cleaner, directly under the Vacuum Motor.

The basic principle, or how I understand it at least, is that this shroud 'collects' warm air surrounding the exhaust and feeds it to the air-cleaner/carb when the outside temperature is "cold" (a relative word). The Vacuum Motor determines when this warm air should and should not be fed to the air cleaner via a functioning vacuum setup.

I want to try to maintain this system in particular, and re-create the shroud as close to stock as possible - only for my own amusement. I have the existing stock shroud, but it has deteriorated significantly due to corrosion. But, my hope is that it can be used as a template for fabricating a new shroud.

For now, I will only post pictures of the stock shroud from various angles, and also shown together with the exhaust/intake manifolds to give an idea of positioning.

When I have the new shroud finished and test fitted, I will share pictures of the new shroud. I would also like to try to get basic dimensions off the new shroud to share on this thread, for anyone who wants to make their own shroud and does not have the old/stock shroud handy (maybe the previous owner removed it, etc.).

Please let me know if I said something wrong or if you would like specific details. Thanks!

 

Nope, you have the correct idea on theory and need of the system

As fuel mixtures were leaned and EGR was introduced for emissions, this system is necessary.

 

I think making a new shroud is a very good idea and in my opinion is one of the most overlooked items on many rebuilds. It is necessary especially in colder temps - below ~45 degrees to prevent carb icing and poor cold start-up performance. I think it does more good than the exhaust heat on the floor of the intake manifold.

Only two things I want to correct on your description - it is held in place by more than one bolt. Look at the drawing of the parts to see where it attaches...
...and the vacuum controls on later versions did not use a vacuum motor controlled 'on/off gate', but rather the flapper valve was modulated to maintain a consistent inlet air temperature to the carb, around 110 - 140 degrees, by varying the amount of opening with a temperature sensing bleeder valve.

I suggest you make it out of stainless steel, so you will have a lifetime part. The originals did rust out fairly easily in most climates. I think if you made them from stainless steel you could market them to others as there is a relatively large demand for them since they are not stocked by the dealer network. Good luck with your project.

 

I could not find exactly what you are working on, 81F(ranken)100, but this is what was used in earlier years on the 240 engine.

https://www.ebay.com/itm/NOS-OEM-For...BVns8C&vxp=mtr

 

And here is a photo of a rusty one found on eBay [just so we all can envision what you are going to make].

 

This "auto parts store" copy of the Ford truck parts catalog pic was cropped (it's missing the details on the right).

It was originally drawn for 1975/79 F100 300. Ford truck parts catalog: Ford recycled the pic for 1980/86, changed the captions.

So what you see inre to the 9A607 shroud will not be the same as 1975/78, not the same as 1979/80, not the same as 1981/86!

 

I've said it a gazillion times before and I'll say it again: Most ebay sellers haven't a single clue what parts fit, even if they're NOS with a part number marked on it!

C5AZ-9A603-A .. Carburetor Air Cleaner Air Duct Shroud / Obsolete

1965 Galaxie/LTD 352/390 with M/T; 1967 F100/350 352 from serial number A84,001.

The correct 1965 Galaxie/LTD 240 I-6 shroud is C5AZ-9A603-B

Also see post #6.

"Alabam" is not to blame, he just dug up this hogwash from an ebay ad.

 

One of these days, "Alabam" will stop trying to find obsolete items and leave it to the ones who really know. Thanks for your input, Mr. NumberDummy.

Upon closer observation, it is obvious the eBay listed part will not mount to the manifold of the 240/300 stock engine. The two mounting holes are configured to mount "straight in" rather than "up".

 

depending on where you live i could let you have mine, its just fine, unless of course you just want to make it.

 

Thank you FTF, ND, and everyone else for your input!

I'm still on a business trip in Germany and will 'get back to it' soon (I hope). I might take 78Fords up on his offer, if indeed it's the correct shroud (as ND pointed out). Either way, I will certainly update with progress/drawings/pictures when I have something new to report!

-Adam