I had the similar problem on the '81. They used seam sealer on those later years I guess. The sealer was hard and brittle.
So I removed the wiper arms, transmission, wiper arm towers. Then chiseled out all the old seam sealer in the wiper tray area and went down along the sides of the cowl that I could reach. Then I picked up some good professional grade seam sealer from the local auto body supply store.
Then placed tape on both sides of the seams, then laid the seam sealer along the seam and in between the tape. Once the sealer was starting to set up I peeled up the tape leaving a nice clean line. Then once it was cured I took some "paintable" undercoating and did a couple light coats. Once that dried I took some satin black paint and dusted in a few coats.
Haven't had a leak in years, and it still looks good in that area.