If I cut some Aluminum strips (we make flashings) into the correct dimensions and made basically a box without a top and dropped it into the cowl and sealed it up with caulking and made a drain on either end that was basically just a tube and ran it out the bottom of the car, would that work?

I am at work so I dont have time to search but I remember searching before and finding that the cowl is basically just for fresh air right? Would I be able to do this and make cut outs for fresh air into the cab?

Then i would have a new aluminum cowl resting on the rusted out original cowl, full sealed with 2 drain holes(and tubes).

Do I need holes for air? Can I still get heat without holes into the cab?

I doubt this will work but an explanation of why would be awesome, thanks guys!

 

By the time you did all that and had a cobbed up solution, you could have replaced the cowl properly. Don't get me wrong, I'm all for new ideas and doing things differently, unless there is a good fix already.

 

that seems like a bit of a pain in the rear because you would have a hard time getting your aluminum tub into the existing cowl cavity. Are you painting the car? If you want an easy fix you could weld panels over the cowl vents so it would be flush. You would still have a rusted out cowl but water should not be able to seep through.

 

not to sound stupid, but what purpose is the cowl vent? Doesnt it take away for whatever purpose it was intended if you cover it up/

 

my understanding is that it allows air to vent into the car.

 

It does allow air into car (heater box) and vent panels. Before I fixed my cowl I had it covered for a couple years. Now that I fixed it sure is nice being able to open vent on kick panels in.

 

The cowl has two air inlets to the interior of the car. The inlets have water dams that allow air to come over the top, but channel water around the inlet to the drain opening under the fenders on each side. The driver's side goes into a vent controlled by the driver via a cable. Pull it out, it opens and outside air comes in, push it in and it closes. The passenger side feeds the heater box. It is controlled by a cable from the heater control panel (TEMP). When open, it allows outside air to come into the car and through either the defroster (DEF) or heater (HEAT) opening into the interior. Here is the control panel from a 65/66:

 

We repaired our cowl by using the "tin can method".
Here is our webpage with pictures and reference site if you need to replace the top hats without drilling the 300 spotwelds.
http://chris66dad.tripod.com/id18.html

 

Tin can method described by chris66dad would be the way to go. You can leave the glass in and have the satifaction done right and not have a rusted metal lurking below. I'd cover them with those plastic covers for vents until I had time or funds to do right.

https://www.mustangsplus.com/xcart/p...at=2321&page=1

 

I would replace the rusted out metal with patch panels. It's one of those things that needs to be right so later on down the road this problem doesn't re-occur.