My brain isn't braining on why the a-body would leak if those tiny holes were plugged.
Now I can't wait to r&r my windshield.
And I'm not doing because it leaks, doing the rear because it's rusty and leaks and figured do the front at the same time.
Because water would go under the rubber gasket as it was not "glued" to the metal structure all the way along. The holes were a way for the water to exit via the cowl drains. If plugged off, the overflow would be into the interior.