1984 Bronco XLT 351W 4180C carburetor - which port is for vacuum advance PLEASE RESPOND

[MaineBroncoBeast]

I couldn't find an answer so I hope someone can.

I have 2 ports on the base plate, one small, the other large. The large goes to PVC valve.

I have 2 ports on the throttle body, one small, the other large. The large with a big blue rubber vacuum cap.

Where does the vacuum advance line go?

 

[L\Bronco]

I couldn't find an answer so I hope someone can.

I have 2 ports on the base plate, one small, the other large. The large goes to PVC valve.

I have 2 ports on the throttle body, one small, the other large. The large with a big blue rubber vacuum cap.

Where does the vacuum advance line go?

The vac advance line goes to the small port on the front lower rh (pass) side of the carb. beside the capped off big one. (I have an 85 351HO parts truck in the field and I just looked at it)
Hope that helps.
Cheers

 

[L\Bronco]

sorry, I was too slow. It's a long walk.

 

[MaineBroncoBeast]

Thank you, but was that the bottom baseplate or the throttle body? There's a big difference. I put the distributor vacuum advance on the small port throttle body and purge vacuum on the small port baseplate and everything went to crap real fast. Tried starting the engine and it cranked really slow and when it did start, It went from 20" hg to 10" hg. So I put it back how I had it.

Are you sure that carburetor is a 4180C E4TE-9510-ARA LIST 50174?
Can you take a picture of the carb and part number (on the front horn of carb body)?

Thanks

 

[Motech]

As you can see, this vacuum diagram from Ford is a flipping spaghetti mess!



Following back from the distributor, it tees off the "S" port, AKA Purge hose. This is a ported vacuum source, and if you follow the black hose right underneath the "PURG" label it tees to, you can see how intense that side gets.

Thank god and Blue Oval that no such heinous spark controls are installed, cuz even though it tees into that complex purge system, your vacuum advance signal comes straight-up from an unencumbered, ported vacuum source.

Best online shots I could find, this is a 5.0 Mustang setup, but same source at arrow.



Here's another shot on engine, it's the faded white hose straight up top



Number 1 in this shot



Hope this helps.

PS Edit:

Once hooked up right, the "ported" vacuum source will have no vacuum at idle, and will begin to flow progressively more vacuum with throttle opening.