Couple things...
The first thing that should go on when assembling the front sheetmetal is the hood and everything aligns off of that. The reason is that the v-shaped gap at the rear has to be even and the only thing that can adjust that is the up/down position of the front of the hood and the alignment of the hood latch determines that... assuming the cab is sitting correctly on the frame.
Secondly, there is an adjustment for the problem you are having. Go to the Body section of the Shop Manual and you will find instructions there... but 1 to 3 inches sure seems like a lot.
HERE'S THE LINK Hope this is just trial fitting and not finish panted parts we're talking about here.
Good luck.
