The cowl vent hood helps cool your engine bay by thermo-siphon when idling or after shutdown to help prevent vapor lock and protect wiring and other components from heat cycling. It is designed to bolt onto the factory hinges, utilize the factory latch, and the original hood vents (or our Subtle Z™ hood vents) for additional cooling. The vent recesses are identical to the factory hood, so vents bolt right on. But holes are not pre-drilled in case you want to bond your vents.
The cowl vent hood also takes advantage of a high pressure area that forms at the base of the windshield when moving (which is why your fresh air vent is located in the cowl) to enable cooler air flowing downward across the cylinder head and out the bottom of the engine bay.