Bad idea. The area directly in front of the windshield is a high pressure area. Raising the rear of the hood will allow that high pressure air into the engine compartment and increase the air pressure on the back side of the radiator. Raising the pressure on the back side of the radiator makes it even harder for air to flow through it from the front and will reduce your cooling efficiency. If you're wanting to reduce underhood pressures in order to increase the airflow through the radiator, a hood vent directly behind the radiator is your best bet (the center of the hood is low pressure). Look at performance cars like Vipers, Lotus Elises, & Ferraris and note where their hood vents are located.