Bought a 86 F250 5.8 HO air cleaner, what is this on the side of it?

[FordFETruck]

After years of trying to find a decent 86 F250 351W HO air cleaner assembly I finally found one. I probably paid a bit more than I should have since I had to pay shipping but all the ones I found locally in the past were beat to death or on fire. This one is in good shape minus the vacuum motor but that's no big deal. It also came with the cold air snorkel in great shape. What I haven't seen before is this vacuum actuated trap door on the side of it. It seems to me like it opens under low vacuum for more airflow capability? I've only seen these on 460 air cleaners but this came off of a 86 F250 8500 GVWR 351W HO C6 truck from a junkyard and looked all original under the hood from the pictures I saw. Anyone know what the actual purpose of this thing on the side is? can't seem to find a vacuum diaphragm for it, I may just wire it shut or remove it and plug the hole with the flap door it has.  

[Gary Lewis]

That's the 460 air cleaner as you thought.  As for how it is plumbed, below is the vacuum diagram from Bill/85lebaront2's Darth and I think what we are talking about is the A/CL DV: Air Cleaner Diverter Valve.

[FordFETruck]

The air cleaner lid is also painted black from the factory. Interesting that truck had the wrong air cleaner housing on it. No big deal either way though if that's the only difference. It is WAY more heavy duty and sturdy feeling than the all-aluminum air cleaner housing I have on it now, that one came from an 81 F150 351M truck and it's not in great shape. Not sure if you remember or not, but we did some air inlet hose swapping years ago via mail when I got it from the junk yard. Is there a part number for the vacuum pod in that air cleaner diverter valve? would be cool if it worked but no big deal if it doesn't.

I also found another air cleaner housing just like this on another 351W HO truck online also in a junkyard, not sure if the highest GVWR trucks came with it and the standard GVWR didn't?

[ArdWrknTrk]

Seems more than a few last year H.O.'s had these air cleaners.
I expect Ford didn't want to be sitting on them.

I've done a lot of searching and have never found a replacement for the vacuum motor that sucks the trap door closed when the engine isn't WOT.

[Gary Lewis]

I can't say that the 460 air cleaner was never put on a 351HO, but I'm pretty sure that's what you have.

As for the vacuum motor, I think that will take some research.  You can go to the page at Documentation/Calibration Info & Part #"s and then the Application To Parts List tab.  Scroll down to the 460's and write down the parts list numbers.  Then go to the Parts List tab and scroll down to those lists and look at the 9D612's, which is the base # for the vacuum motor.

Hopefully you will find some parts list that has two vacuum motors.

[FordFETruck]

I get the hunch it actually is a 460 air cleaner too. I may just delete the diverter valve since it's not really needed. I did find a new vacuum motor for the blendoor though. I did a test fit today then scrubbed the thing down. What do you all think, all black, black with silver/aluminum top or gunmetal metallic grey with silver/aluminum top?IMG_20230221_132324.jpg

[85lebaront2]

There were two vacuum motors on the 460 air cleaners, on on the right (passenger) side that was thermal controlled and picked up heated air from the right exhaust manifold through a sheet metal jacket. The other was on the back side of the air cleaner and was only vacuum controlled and would open under wide open throttle.

[ArdWrknTrk]

Your image is too large for this antiquated system. (Select 'large size' in the options)
I'm not really sure which way I'd go with your engine colours.
Probably Silver/Black as I think a little contrast is good.