Copied from Resto Rick's site.... I know it sez E body & 71 & up B but it will help your car too...

A common alignment problem on E-body & 71-up B-bodies is the rear edge being up too high with the hinges being adjusted all the way down on the inner fender.
This is an adjustment problem! Start by moving the hinge up on the inner fender. (yes, up!)
Then, loosen the 2 rear bolts and leave the front bolt snug. Now lift the hood to make the hinge rotate (as viewed from the side). Retighten the rear bolts and check the fit. This procedure will get that tail to come down. Adjust the front-to-rear dimension on the hood side bolts.
It can be frustrating and take some time, but these hoods will fit correctly! I’ve installed them with the hood sitting about 2 1/2" above the fender! Within a few minutes it was fitting perfect!