Hood pops up a little from road vibration

My 70 Challenger hood is flush with the driver's side fender when parked. When I drive it vibration from the road makes the hood pop up about 1/2" in the rear. When I stop I push it back down but once I start driving again it pops back up. I have the hood hinge bolted down as far as it will go on the inner fender apron. Has anyone had this issue or know why this is? Thanks.
Author: 70SunFun