This is a very rare option for the 1969 - 1970 Mercury Cougar, Ford Mustang, and Shelby Mustang. It utilizes a center dash AC vent to blow fresh air into the cabin. The heater box is very similar to the standard heater box / plenum but has the vacuum switch and bracket mounted to the top. As our pictures will show, we are very careful to remove every nut bolt and clip. The unit shown was taken from a 1969 xr7 convertible equipped with a 390 with only 80k miles.
Click on images to enlarge.
There are two of these vacuum switches utilized in this system. One is located at the top of the plenum and one at the controls. We have this item available new in our AC section.
There are several of these two piece plastic fasteners used to connect the ducts to one another.
There are two of these unique fasteners used to hold the chrome center vent to the dash pad. Keep in mind the Mustang utilizes a different chrome register / vent than the Cougar one pictured here.
Notice the extra tab welded to the door shaft. This of course is needed to activate the vacuum switch.
To test these in line vacuum check valves, put the larger nipple to your mouth and breath in, then blow. if you can blow it is a bad valve.
