Not sure of the cause but the remedy is taking the hood off and then the hood hinges. Once the hood hinges are off long gate the back hole (one nearest to the cowl) at the top with a rat tail file. Remount the hinges and hood then have some one put pressure ( lifting up on the nose of the hood) so that hinge is as down as far as it can go then tighten the two hood hinge bolts.Should take care of the problem with the hood sticking up.
Reason is either misalignment or worn hinges. Remedy; 2 people. Loosen the 2 bolts on each side of the hinge to the fender well. Lift the hood up pushing against it while it's fully opened. Tighten the 2 rear bolts up first the closest to the windshield and then the other 2. Should solve the problem.
Paul Winvoices. Experts in reproduction documentation for the 1959-1988* Chevrolet line. Please visit our website: http://www.winvoices.com * Restrictions apply