Years ago I had a '54 that had the same problem. The edge of cowl vent has a little gutter around the opening which drains the water to the hose going through the firewall. The gutter on my truck was rusted out so I removed the air scoop the opens and closes and repaired the gutter with fiber glass and put the scoop back in. It worked pretty well from what I remember. That was in 1978 or so. I don't remember how difficult it was to remove the scoop.
Jacques


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