67 A/C cab

[Arizona oldguy]

I am finally putting my truck back together, I shaved the firewall and will not be using the factory A/C (sorry it’s long gone) my question, I remember (barely) removing the plenum door or valve that was in the cowl. If I am not using the old system, do I need this? I do have the kick panel vent doors and the vacuum actuator for the passenger side and lever for the drivers side.

Thank you for any help

[Rods]

Originally Posted by Arizona oldguy

I am finally putting my truck back together, I shaved the firewall and will not be using the factory A/C (sorry it’s long gone) my question, I remember (barely) removing the plenum door or valve that was in the cowl. If I am not using the old system, do I need this? I do have the kick panel vent doors and the vacuum actuator for the passenger side and lever for the drivers side.

Thank you for any help

If you convert the vent inside to a manual operated rather then the using the the vacuumed for fresh air venting you could keep it as is and operate it manually.

[Andy4639]

If you doing away with the AC then yes it's not needed. But you do need to make the kick panel vent manual. Well you don't have to but I have never seen one that wasn't. You will have to change the controller out to are figure out which cables to hook up to operate it correctly.
The AC & heat are different designs.

Heat is operated by the arms only the AC operates with a fan switch.

[Getter-Done]

Here is an Old post I had wrote down for reference when
I get to this stage in my build.

Link: http://67-72chevytrucks.com/vboard/s...d.php?t=518197

Here is another one I found today.

Andy helped in the link below also.
Link: http://67-72chevytrucks.com/vboard/s...ad.php?t=76770









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[Andy4639]

You have to remember that the diaphragm's all look alike but depending on what year model they came from will determine how they operate.

Adding vacuum either opens are shuts them. There is no way to tell by looking at them that I know of.

On my 71 C 10 I took the cowl vaccum diaphragm out & the flapper all together. I permanently sealed it off. I also swapped the passenger side kick panel back to manual and I leave it open all the time. This in effect does the same thing as in a late model vehicle on recirculation air. It keeps the cab air recirculating to make it colder without adding outside air.
It works great and if you need some fresh air just open the drivers side kick panel are a window. It keeps the truck nice and cool during the middle of the hot summer no matter how hot it gets.