gas smell in cab

Two guys mentioned a possible opening in the firewall which brings up a short story. Back in high school I read that the area at the base of the windshield produced a high pressure area when the car was moving. So I ran a couple of 4" hoses from the air cleaner on my 68 Roadrunner to two holes that I cut in the firewall to get a little boost. WRONG!

Gas fumes would flow right from the engine compartment into the car ventilation system -- mainly when the engine was off.

The point is that any gas fumes that get past the firewall into the area below the cowl, can easily be sucked into your car.