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  1. #1
    FEP Member 86-123's Avatar
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    Default Non-a/c hvac box differences

    I am looking to make my 86 coupe a no option car and will need a non-a/c hvac box. What years can I use to remove the a/c system. I will also be looking for a heater control panel for the dash. Other than those two items is there anything else that I will need? Thank you.


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    - Bob
    - 1992 Twilight Blue Lx 5.0
    - 1991 Saleen #045 Twilight Blue vert with a blue top- SOLD
    - 1986 Saleen #123 37k original miles- SOLD
    - 1985 Mustang Lx 5.0 5spd conv.- SOLD
    - 1986 LX 5.0 coupe-SOLD

  2. #2

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    I recently went through the exact opposite swap. You may also want the manually operated vent pulls as well as a block off plate for the firewall holes you will no longer be using.

  3. #3
    Moderator wraithracing's Avatar
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    Default

    The short answer is that you should be able to make any of the 79-93 NON A/C boxes work for your coupe. If possible buying one from an 83-86 will most likely be the most "bolt in" option. Don't forget you will need the manual controller too for the box since the A/C boxes use vacuum and the non A/C units are all manual. I know I have several manual controllers if you need one, just send me a PM. Good Luck!
    ​Trey

    "I Don't build it hoping for your approval! I built it because it meets mine!"

    "I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."

    Mustangs Past: Too many to remember!
    Current Mustangs:
    1969 Mach 1
    1979 Pace Car now 5.0/5 speed
    1982 GT Stalled RestoModification
    1984 SVO Still Waiting Restoration
    1986 GT Under going Wide Body Conversion Currently

    Current Capris:
    1981 Capri Roller
    1981 Capri Black Magic Roller Basket Case
    1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
    1984 Capri RS T-top Roller
    1983-84 Gloy Racing Trans Am/IMSA Body Parts

  4. #4
    FEP Member 86-123's Avatar
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    Default

    Thank you for the replies. When we say vent pull or manual controller, are we talking about cables and the dash controller? I just decided to do this in an attempt to make it a factory light weight and haven’t started looking for the parts yet. I just want to be as prepared as possible so that I get all the parts needed on the first try. Thank you.


    Sent from my iPhone using Tapatalk
    - Bob
    - 1992 Twilight Blue Lx 5.0
    - 1991 Saleen #045 Twilight Blue vert with a blue top- SOLD
    - 1986 Saleen #123 37k original miles- SOLD
    - 1985 Mustang Lx 5.0 5spd conv.- SOLD
    - 1986 LX 5.0 coupe-SOLD

  5. #5
    Moderator wraithracing's Avatar
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    Default

    The non A/C cars had manual vents that had a pull lever under the dash that allowed fresh oil in from outside the car through the cowl vent holes. The actual vents screw into just above the kick panels in the hinge posts on either side.

    The NON A/C control unit in the dash is all mechanical using only levers and cables. The A/C cars use a lever and cable for the temperature door, but all the vents are controlled via vacuum and vacuum controlled dashpots/solenoids that operate the different blend doors to move the air from defrost, to vents, to floor. If you swap to a NON A/C box you will need the matching control unit in the dash to control the blend doors in the box to move the air from defrost to vent to floor. Good Luck!
    ​Trey

    "I Don't build it hoping for your approval! I built it because it meets mine!"

    "I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."

    Mustangs Past: Too many to remember!
    Current Mustangs:
    1969 Mach 1
    1979 Pace Car now 5.0/5 speed
    1982 GT Stalled RestoModification
    1984 SVO Still Waiting Restoration
    1986 GT Under going Wide Body Conversion Currently

    Current Capris:
    1981 Capri Roller
    1981 Capri Black Magic Roller Basket Case
    1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
    1984 Capri RS T-top Roller
    1983-84 Gloy Racing Trans Am/IMSA Body Parts

  6. #6
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    Default

    The 79-84 is different than the 85-86, the 79-84 had the pull vents and only had two vents one on the drivers side and one on the passenger side. The 85-86 had four vents in the dash and no pull vents under the dash. By the way the firewall is different on the air cars and non air cars. The holes for the heater core are in different places.
    Kendal

  7. #7
    FEP Member 86-123's Avatar
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    Default

    Thank you for the information. Can an 86 be converted from a/c to non-a/c or vice versa with the heater core differences or would the firewall need to be altered? I converted an 89 to non a/c years ago and it was a straight swap. I was hoping this was doable also. Thanks.


    Sent from my iPhone using Tapatalk
    - Bob
    - 1992 Twilight Blue Lx 5.0
    - 1991 Saleen #045 Twilight Blue vert with a blue top- SOLD
    - 1986 Saleen #123 37k original miles- SOLD
    - 1985 Mustang Lx 5.0 5spd conv.- SOLD
    - 1986 LX 5.0 coupe-SOLD

  8. #8
    FEP Power Member
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    I have changed them back to non air after someone added air to a non air car. You will just have to drill new holes for the heater core and fill in the old ones. You will need a 85-86 heater box and the center connection tube. I am pretty sure the other tubes are the same. The 79-84 box doesn't connect to the outer vents, they hook up to the cowl.
    Kendal

  9. #9

    Default

    Figures, I was just looking for a thread about going the other way. Considering putting A/C back in my 86 Mustang so I can actually drive it in the summer heat.
    1986 Mustang Notch, 2.3L Turbo Project

  10. #10
    Moderator wraithracing's Avatar
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    Default

    Just an FYI, the firewall is not actually different. The difference is the opening for the Evaporator tubing is not cut. The embossing is there for the cut out, but just not cut out on the NON A/C cars. As stated above the heater core tubes exit the firewall in a different location between the A/C and NON A/C cars. Converting one way or the other is nothing more than gathering the correct heater or HVAC box, misc duct work, and control panel and then swap as needed. Obviously converting to A/C requires some additional electrical wiring for both the control unit and the compressor. I did the swap from NON A/C to A/C on my 79 PC that has the earlier firewall that doesn't have the embossing for the evaporator cut out. I made a template off a later model with it. Cut the hole and installed an 85/86 HVAC unit and controller and the A/C was working well until the crankshaft took out the thrust bearing.
    ​Trey

    "I Don't build it hoping for your approval! I built it because it meets mine!"

    "I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."

    Mustangs Past: Too many to remember!
    Current Mustangs:
    1969 Mach 1
    1979 Pace Car now 5.0/5 speed
    1982 GT Stalled RestoModification
    1984 SVO Still Waiting Restoration
    1986 GT Under going Wide Body Conversion Currently

    Current Capris:
    1981 Capri Roller
    1981 Capri Black Magic Roller Basket Case
    1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
    1984 Capri RS T-top Roller
    1983-84 Gloy Racing Trans Am/IMSA Body Parts

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