Trying to source a replacement air box for the 87 ford f150 5.0L air box. Mine has 2 broken mounting screw fasteners.

The ones I have seen for sale on eBay and on Bronco graveyard do not have the 2 vacuum line connections. Are these
necessary? I'm assuming these are for emissions or some such related functionality.

 

Vacuum lines? On the air filter box? Got a picture?

 

ya, apparently 87 was a test year pre-MAF where they used heater riser plates for the intake with hot air from the exhaust manifold when the
engine is cold. Not sure what the other vacuum line is for though.

see below:

 

And where do the lines go?

I don't think that is factory, but I can't claim to have seen it all by a long shot.

 

factory option for cold climates from what I have read. the side closest to the firewall goes to the vacuum tree. the other nipple hose goes to a vacuum driven
motor on the air input snorkle. This actuator lets air in from the exhaust when the engine temp is < 100 deg to warm the throttle body. when reaching that temp
the vacuum is SUPPOSED to be stopped, thereby closing the input from the exhaust manifold. There is a round metal valve on the inside of the top of the air
box lid that controls this. I'm wondering if this valve has failed and is letting the vacuum thru all the time possibly incurring a vacuum leak.

see below:

 

Interesting. Hadn't seen that on an efi set up. I would think you could just delete it.

Remove the line on the vacuum tree and cap the port to test whether or not it is causing a running problem.

As far as the air box goes, the lid bolts go into captured nuts in the base. If they are damaged you could possibly remove them and replace them instead of buying another box (F4TZ9600C). Not sure how easy that would be, but it is a thought.

I might have a box in storage. I will look.

 

I had attempted to "fix" the captured nuts in the bottom lid but they just spin again. I see people selling the lower part on eBay.
It is more a cosmetic thing at this point. Just something that annoys me. 3 of the 4 lid screws are working so it holds down OK.

Once the rain stops, I'll do a test of the vacuum being supplied to this valve and see if in fact it is broken.