I did this on my 68 due to rust issues. With a little patience and a spot weld drill bit it can be done cleanly. I drilled the spot welds across the lower windshield edge (at the cowl panel area). Then there are 3 mounting tabs, two on either edge by the "A" pillar base, and one in the middle, near the radio area. It sounds primitive, but cut those with a sawzall and the whole dash face and top will come out. The fun part is finding a clean original 67 piece to put back in. Now if you car has factory a/c, you may need to leave the "face" in place for the vent/duct holes. If that's the case, drill the spot welds across the upper dash (behind the pad) and just remove the dash top that has the 68 VIN hole. Good luck!