Thought I would share some pictures of what makes up the heater delete option for others to see and discuss. Unfortunately I don't have a collection of all of these parts so I have to rely on my collection of pictures instead
Because of where the car was being shipped, optioned or how the original buyer choose a very few Mustangs each year received no heater.
65-66 Heater DeleteBefore the interior firewall pad was installed a semi-gloss black painted heater delete panel was installed to the firewall on the passenger side and two rubber plugs were installed (pushed in) the heater hose holes
This well used example (68 Dearborn) shows the heater punch out still in place
On the passenger side interior where the heater normally would attach to the cowl vent a special duct with manually operated door was installed in place of the heater.
And in place of the heater controls a small plastic plate was installed which had s metal bar on the back to retain it to the dash surface
At the engine the heater hose connections were capped off using short rubber plugs and the normal (for the year) heater hose clamps
On cars with this option a firewall plate was installed before the firewall pad was installed. On factory firewalls some of the holes were punched and the section was removed or in the case of a heater delete the section was prepunched but the section was left attached