I wonder what type of modifications were done for it to fit ?
I've never done it, but believe it wouldn't be hard to do. The Upper Grille Filler Panel is the same width on all trucks (they share the same hood), and I think it's the same for the Lower as well (3000 vs 4000/6000). I believe a little surgery would be required to the 4000/6000 fenders at the grille area next to the headlights so the small truck grille can slide in. The small Grille Lower Panel is much thinner and would have no issues crossing over the frame rails.
Mike B
