Vacuum hell
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Cross-Country
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From: Billings
Vacuum hell
I picked up a 1984 F150 with a HO 351 4 BBL (Woohoo!) and I can't believe the nightmare of vacuum lines under the hood. I want to get rid of as many as I can to clean things up. I need some suggestions and maybe a good schematic. I know the HVAC system is operated by it byt I am removing the AC. It will also get headers and and I am putting on a Holley aftermarket carb. I will post some pictures in the next day or so. Thank you!!
FTE Legend
Joined: Nov 2015
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From: Angier, NC
Even removing the AC you still need vacuum to the controls or it will not change from defrost to floor or vent as that is controlled by the vacuum.
Only the temperature is controlled by a cable.
I am guessing the distributor has vacuum advance you will need ported vacuum from carb to it.
HVAC manifold vacuum
Power brakes manifold vacuum
PCV manifold vacuum
If you plan to use the truck in the cold / winter the factory air filter needs manifold vacuum and a way to get heat from the header tube(s) to the snorkel.
You can try a open filter but may run into carb issues with icing up and ruff running when cold.
Cant think of anything else ATM
Oh the fuel vapor canister(s) under the battery you can try plugging the line to the manifold and see if you have any issues from fumes, the new carb will not have a float bowl vapor nipple.
Dave ----
Only the temperature is controlled by a cable.
I am guessing the distributor has vacuum advance you will need ported vacuum from carb to it.
HVAC manifold vacuum
Power brakes manifold vacuum
PCV manifold vacuum
If you plan to use the truck in the cold / winter the factory air filter needs manifold vacuum and a way to get heat from the header tube(s) to the snorkel.
You can try a open filter but may run into carb issues with icing up and ruff running when cold.
Cant think of anything else ATM
Oh the fuel vapor canister(s) under the battery you can try plugging the line to the manifold and see if you have any issues from fumes, the new carb will not have a float bowl vapor nipple.
Dave ----
Mountain Pass
Joined: Jun 2022
Posts: 190
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From: SW Connecticut
I picked up a 1984 F150 with a HO 351 4 BBL (Woohoo!) and I can't believe the nightmare of vacuum lines under the hood. I want to get rid of as many as I can to clean things up. I need some suggestions and maybe a good schematic. I know the HVAC system is operated by it byt I am removing the AC. It will also get headers and and I am putting on a Holley aftermarket carb. I will post some pictures in the next day or so. Thank you!!
Fleet Mechanic
Joined: Jul 2013
Posts: 1,997
Likes: 237
From: NE Ohio
I picked up a 1984 F150 with a HO 351 4 BBL (Woohoo!) and I can't believe the nightmare of vacuum lines under the hood. I want to get rid of as many as I can to clean things up. I need some suggestions and maybe a good schematic. I know the HVAC system is operated by it byt I am removing the AC. It will also get headers and and I am putting on a Holley aftermarket carb. I will post some pictures in the next day or so. Thank you!!
chilton manuals should also show it. air filter uses vacuum to operate valves as well.
Lead Driver
Joined: Jun 2013
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From: Tolland, CT
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From: Billings
Maybe see page 118 here,
https://www.garysgaragemahal.com/1984-evtm1.html
https://www.garysgaragemahal.com/1984-evtm1.html
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