Help me identify this part..

I THINK that is the vent and it should be attached to your dash controls under your radio. I could be wrong though.

Pour some water in your cowl outside of your car and see if water leaks in through there. Is the piece broken off or rotted off?

It's a manually operated door that lets fresh air (and tempered air?? not sure) into the car and is not linked to the controls under the radio. It's out of sight under there, so you could fix it with a bit of ply or fibreglass or something, or you could buy a complete new box - I don't think they do just the door. Replacement will involve draining all your coolant, removing the defroster ducts, disconnecting the control cables and undoing the four nuts that hold the fan motor to the firewall. It sounds worse than it is, but it'll take you a couple of hours to do.

ssounds like the heater box door..

Just for the record, there is rarely such a thing as a "no rust all original sheetmetal car" unless it has never seen the light of day, in particular the cowl of a 65-68 Mustang. Even if your cars body and undercarriage has been very well cared for, rust free and never ever driven in the rust belt of america, if it has been out in the rain even only once 40 years ago when delivered from the dealer to the garage it likely has some form of cowl rot even if it is just the surface. I am not doubting you in any way shape or form mind you so please dont take offense but Ford never expected these cars to be around for more than 10 years and as such they never ever put any kind of paint or protection on the cowls in the first 4 years of production, it is totally bare metal and often the drain holes were plugged with body seam filler. The slightest bit of moisture in the air could make them rot over time much less a an 1/8 of inch of water that sat in there even just once in 40 years until it evaporated. Check around and poor some water in it to be sure as many of the cars sold have not had this done, it is costly and expensive to fit so almost all of them need it.

hey pak
when I got my car there was NO rust at all. AZ car. the sad thing is now that I have it on the cape every time I look at it I find more and more rust But like i said before there was NO rust when I got it. even My body guy couldnt believe it.

I have two zero rust cars from California and I have seen the cowls on both. It can be done.

Hey I have a rust free San Hose car as well that I bought with a documented 46,000 original miles on it to boot so I know it's not impossible. More often than not though folks who "believe" they purchased a rust free car in fact did not, I just wanted to make sure he knew that. Everyone has a different opinon of "rust free" too. Unless a car has been air tight sealed it's entire life you can find even the smallest spec of rust somwhere on just about any car shy of a fresh rotiserie restoration. It was easy for me to verify the condition of the cowl on a 69', not so easy to do on an earlier car though so usually one can not really know for sure until the car is torn into. I mean even in a desert that never ever sees rain, odds are somone washed it at least once and so unless the somehow managed to to towel dry the inside of the cowl too........

Anyway, it wasn't doubt as I prefaced, just precaution.

Glad you got yourself a good one!

Zero rust original panel cars are not that rare in CA