The measurements are a starting reference point. Every A.D. truck will be slightly different for any number of reasons. Install the hood 1st. You get a good hood alignment at the upper cowl and side cowl by adjusting the hood hindges as necessary. Then you align the front fenders etc. to the hood by adjusting those diagonal rods as necessary , use your eye. You can add or subtract shims from under the radiator core support the raise or lower the (nose) fenders to get a good alignment of the hood sides to the fenders and the hood front to the grille.
