65-66 owners or ex owners please respond

[jwboner]

You are right. The 40 year old design isn't that good compared to today's standards. And just blowing hot air on the windshield doesn't always cut the frost away.
The best advice is to remove it and get a modern a/c unit and defroster in one from Vintage Air or somebody like that.

[dav65mus]

I have owned 6 different 65-66 mustangs over the last 28 years and back in the day when I was in highschool (80-83) I hated the defroster on my 66.

I used to carry a roll of paper towels in the car with me and when it was cold and damp I would wipe the moisture off of the inside of the window

I did not have a leaky heatercore or hoses, it was just humid,cool, Louisiana winters.

The previous poster hit the nail on the head.... new cars have dehumidified defrost air.... old mustangs don't.

I currently own 2 65 stangs a coupe and a fastback, but they are only fun good weather drivers so the defrost does not matter.

You can get a modern air/heater/defrost setup made for classic stangs that will work like a newer car, but they run around $1k for a kit.

Good luck