• 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Vacuum hose routing
I think the only one he has in that thread is just that one.

“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
What a great job of taking pictures as you go. David did a lot of work. Never fails though, the more pictures I see, the more I look, the more I want.
Can never have too many.
Got lost going through the thread and will now get back to focusing on the pics about the original question.....vacuum lines.
So looking at the 250 and 302 calibration schematics for 73 that I have access to, which is not many, there are similarities in those that specifically state with or without AC.
Specifically 3-8C, 3-9, 3-11C, and 3-11E, in that the main difference appears to be that when showing with AC, a 3 port water temperature actuated switch is introduced into the vacuum advance circuit to change from one vacuum source to another. Could one stretch this to the conclusion that if AC was added to a 351C calibration you would add the same type of circuit? Being the Clevelands have dry intakes, the choices for a water temp switch is limited. Helps explain why the 2 port switch for the EGR is in the heater hose.

Don't believe Ford wanted to spend too much time on this in 72-73. They were working on the next Better Idea......the Mustang II.

Probable that there really aren't any "magic diagrams" that show it all. In my opinion, calibration drawings are just that, they show Emission Calibrations and information. A "full-up" vacuum drawing would have AC lines, ram air, manifold vacuum trees, brake booster, choke, air cleaner, the double vacuum loops on the firewall, and so on. Too much data for one page I think. I would assume that other stuff would be in another section of a service manual. Perhaps there is something elsewhere that shows what happens when you add AC to a 351?? Perhaps in a Technical Service Bulletin?

Looking at this post 
which also appears to be an unmolested 351C with AC, you can see a 3 port switch in the water pump. In other pictures on the same page, it has been removed from the pump and is hanging next to the outside of the right valve cover.

No answers, just more questions.
[+] 1 user Likes kingb1973's post
If you want to research the TSBs you'll find a link in this thread.
Good luck.

“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
[+] 1 user Likes Don C's post
That is one heck of a lot "o" Data. Should keep me busy for some time to come. Great link if I can figure out all the online navigation.
If you find anything, please let us know, I'll update my thread with vacuum schematics.

“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
I skimmed through all the TSBs for late ‘72 and most of ‘73 but didn’t find anything relevant to this situation on the first pass.
Did you look at the '72 routing? Some of them look similar to what yours had. Emission controls were new back then and changes happened at various times and not necessarily at model year changes, and there were likely carry-overs.
You can find them here:

“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
[+] 1 user Likes Don C's post
Went to the bookshelf several times this weekend. Swear I looked at the same stuff over and over. tried again and found this early this morning before going to work. Cannot verify the accuracy of what is shown here (Bad pictures of bad PDFs in a fairly good book), but it looks informative. Hope this helps.

Pics are of diagrams for 1973 EGR Equipped 351C in several combinations, (2V/4V, MT/AT, W and W/O AC). Still has some things like the air cleaner that do not look correct, but they do show 2 and 3 port temp switches, 4 port loop on the firewall, mechanical DVAC for manual transmissions, etc.
Have PDFs attached below of these and the 302 and 250. Think if you combine this with the calibrations that Don C has, it just may get you where you are trying to go.

 [Image: 73-351c-MT.jpg]

[Image: 73-351c-AT.jpg]

I don't understand why there are 2 options for the heater hose mounted 2 port switch when having the auto transmission. Attached are pictured that show one type for the auto trans (18B402), don't know what the optional PN 18599 looks like.  The other picture is for the manual trans (18A568). PN 18599 images I can find don't make sense to me. I got these pics from other members when I was trying to figure out how the vacuum lines ran on my 73. 

Here is the link to that post:
Also pic of the vacuum tree in the rear of the intake.

[Image: 18A568.jpg]

[Image: Manifold-Vac-Hose-Fitting-Rear.jpg]

[Image: D3-OZ-18-B402-B-1.jpg]

Attached Files
.pdf   1973 EGR Vacuum Routing.pdf (Size: 1.8 MB / Downloads: 7)
Omigosh, thank you -- Haven't examined closely (project a bit on hold until after Xmas), but at first glance... you may have found it!
Share Thread:  

Possibly Related Threads…
Thread Author Replies Views Last Post
  Lower radiator hose spring RC92234 4 380 12-01-2019, 11:16 AM
Last Post: RC92234
  73 351C 4v ram air vacuum line, where to attach? Zatherith 3 482 10-22-2019, 08:20 AM
Last Post: Hemikiller
  C6 vacuum modulator question mustangandy 4 498 06-25-2019, 03:44 AM
Last Post: mustangandy
  73 Mach 1 351C w/AC vacuum line DeereFanatic 8 848 06-22-2019, 03:45 PM
Last Post: DeereFanatic
  electrical connectors on collant hose? mustangandy 11 633 04-27-2019, 08:45 AM
Last Post: 7173Vert

Users browsing this thread: 1 Guest(s)