During the Rainy Season - I found out my '71 Duster had sprung a leak!

Hi guys. Thanks for your suggestions. They were ALL good. I had my wife help me with the water hose test. I had her in the car, with three turkey pans to tch water. I sealed the hood vents first. We had water come in when I ran water over the windshield. I think it's the original rubber weather-stripping. I ordered a new one. When I changed it around and sealed the windshield with plastic, then poured water on the hood with a hose, with the vents exposed, my wife had me shut the water off. We filled those turkey pans up pretty quick!!
Oldmanmopar-you are a mopar genius! Your pictures speak a 1000 words. I must have vents under the cowl that are chipped, cracked, and rusted out in spots. I have painted, do have heater box and heater core in place now- heater box refurbished and new heater core. So-basically, I'm to get my arm up through the door vent, under the dash, and using the Por 15 Putty, get those holes filled as best as I can. Thanks Everyone. Will keep you posted.