86 Bronco 351 H/O stock carb vacuum line hook-up

Sep 10, 2012
I recently acquired my 86 bronco w/ a 351 Windsor high output with what seems to be a stock autolite 4 barrel carb. I don't quite understand how to read the vacuum chart and not sure where all my lines should hook up. I noticed that on the air filter housing there are 5 places for what seems to be vacuum lines, but not sure which ones go there, and also I believe it is the PCV valves that are capped off. Can anyone help me with understanding where all the line hook up and how to read the chart?


Rons beast

Active member
Dec 13, 2007
Florida..in my mind , sitting on the beach
Hey lil,


The pcv valve should have a line by itself to an engine vacuum port about 3/8" at the base of the rear of the carb.

You only have 1 pvc. For the rest, a pic, or 2 of what you have under your hood would help us alot.

A Bronc that old would likely have something cobbled by past owners and that may be why things are so confusing to you.

Im sure someone else on here has a vac diagram, ( M5, Bully, Krafty, Seabronc, Neb, Adam, others )

But if it doesn't match what you are looking at again it won't be much help.

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96 Bronco 5.0
Staff member
Oct 18, 2005
Coronado, CA

I can't view that URL

Maybe this will help;

Diagram in a 85-86 5.8 Carbureted

Source: by Chilton http://content.chiltonsonline.com/content/images/8576/images/85764183L.gif

acronyms (not nec. for your year/engine); I compiled this from info provided here in da Zone and elsewhere, by SEABRONC and myself

A/CL: Located in the air cleaner

A/CL DV: Air Cleaner Diverter Valve

A/CL BI MET: Air Cleaner Bi-Metallic Valve

A/CL CWM: Air Cleaner Cold Weather Modulator

ACT: Air Charge Temperature Sensor, prior to 1992

ACTS: Air Cleaner Temperature Sensor

ACV: Air Control Valve

AIR: Thermactor, short for Thermal Reactor. CA vehicles are installed with it as standard. Air Injection Reaction is what it stands for.

AIR BPV: AIR BPV is the AIR Bypass (AIRB) Valve; also called the TAB (Thermactor Air Bypass) Valve

BV: Bowl Vent (on top of the carb float tanks)

CARB: Carburetor

CBD: Closed Bowl Distributor

CPRV: Canister Purge Valve

DIST: Distributor

DPFE: Differential Pressure Feedback

DV-TW:Two Way Delay Valve

EFCA: Electronic Fuel Control Assembly/ (Fuel Pressure Regulator (FPR)

EGR: Exhaust Gas Recirculation


EXH HCV: Exhaust Heat Control Valve

EVP: EGR Valve Position

EGR: Valve Position

EVR: EGR Vacuum Regulator; also called EGR Vacuum Solenoid

FLTR: Filter

FPR: Fuel Pressure Regulator (check vacuum line)

HEAT VLV INT: Heat Vacuum Control Valve Intake, (next to carb)

HICV: Hot Idle Control Valve

IAT: Intake Air Temperature Sensor (Air Charge Temperature (ACT), prior to 1992

INT HCV: Heat Vacuum Control Valve Intake

IVV: Thermactor Idle Vacuum Valve

LCV: EGR Load Control

MAN VAC: Manifold vacuum-Vacuum source; usually ref. to as Vacuum Tree atop intake manifold]

MAP: Manifold Absolute Pressure

PCV: Positive Crankcase Ventilation

PURGE: Vapor Canister Purge Valve

PV: Ported Vacuum or Pressure Vacuum

PVS: Ported Vacuum Switch (PVS) Valve

S: Spark port

SA-FV: Separator Assembly Fuel/Vacuum

SOL V: Thermactor Solenoid Valve

SV CBV: Carborator Fuel Bowl Solenoid Vent Valve

TCAC: Thermostatically Controlled Air Cleaner

TCP: Temperature Compensated Accelerator Pump

TK: Throttle Kicker

TVS: Throttle Valve Solenoid (aka Solepot, Dashpot)


TVS: Temperature Vacuum Switch

TVV: Thermal Vacuum Valve

or, TVV: Thermostatic Vacuum Valve (aka Ported Vacuum Switches; Thermal Vacuum Valve)

VAC: Vacuum

VCKV: Vacuum Check Valve

VCV: Vacuum Control Valve

v-cbv: Vacuum Control Bowl Vent port off of the carburetor

VDV: Vacuum Delay Valve

V CK V or VCV: Vacuum Check Valve

VOTM: Vacuum Operated Throttle Modulator

VRDV: Distributor Vacuum Delay Valve (VDV, VRDV, DV-TW)

VRDV: Vacuum Delay Valve (VDV, VRDV, DV-TW)

VRESER: Vacuum Reservoir (coffee can style in earlier years; replaced by plastic style)

VRESV REST: on earlier years such as SEABRONC's 83 is a Vacuum Restictor/delay valve, it delays vacuum for a certain amount of time

VRV: Vacuum Regulator Valve

WOT: Wide Open Throttle Valve

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96 Bronco 5.0
Staff member
Oct 18, 2005
Coronado, CA

Some info on the components shown in the vcuum diagram;

Fuel Bowl Vent Valve Depiction; "...The vent valve is a temperature actuated valve inserted in the carburetor-tocanister vent line. This valve is closed when the engine compartment is cold preventing fuel tank vapors from being vented through the carburetor fuel bowl, forcing them instead into the carbon canister..." - 80.6 MB pdf

AIR BPV: AIR BPV is the AIR Bypass (AIRB) Valve; also called the TAB (Thermactor Air Bypass) Valve

By-pass valves are part of the thermactor system and act to vent air from the air pump into the atmosphere or exhaust

system. Valves may be remote (in-line) or mounted on the air pump.

Air Control Valve

(Secondary Air Injection By-Pass Valve)The air control valve directs air pump output upstream to the exhaust manifold, or downstream to the catalyst system depending upon engine control strategy. This valve attaches to the lines from the air pump

The PCV valve controls the recirculation of blow-bygases from the engine crankcase,venting these gasesinto the intake manifold for combustion.


What Carb is in there?

If 2150 see this 2V Parts Break-Out Diagram; Used on Various V 8 & V 6

Source: by Northernguy at SuperMotors.net

this diagram shows TCP: Temperature Compensated Accelerator Pump

Sep 10, 2012
It looks like the stock motor craft Holley 4180 I believe. I'm not familiar with what most of the components look like but I have been chasing lines trying to figure out where each should go. Do you know by chance how to load pictures?



New member
May 22, 2004
North of NYC
Here is the bare minimum hookup I would use http://www.supermoto...ry/media/672883 Here is one from a 351 HO with dual gas tanks http://www.supermotors.net/registry/media/276766_1 . A truck without dual gas tanks would only have half of the hardware shown at the bottom left. A key connection will be to the distributor, On a stock 4081 that is the port at the top of the carb just above the choke hardware. The two bowl vents should hook to the carbon canister hardware shown at the bottom left of the diagram.

Use the full editor to upload pictures and size them at about 900 X 675 so they will fit on the computer screen. Any larger than that makes them almost useless and takes for ever to display on a slow internet connection.

Good luck,


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