I did the same removal of my dash due to rust issues at the lower windshield area. I was fortunate enough to locate a perfect 68 donor car at a local wrecking yard with a good face,top and radio hole. We drilled the spot welds at the front edge (below the cowl panel/lower windshield edge) and left the seam intact under the dash pad. We made the repair to the lower level cowl panel metal then installed the nicer dash face and top panel in one piece. We then re-welded the spots along the front edge and the two mounting points at the "A" pillar bottoms and the one center dash panel brace (near the radio area) and it looks factory. After a little grinding to the spot welds and a little seam sealer in the right places you cannot tell a repair was made. You do have to re-rivet the original VIN tag on a 68. By the way, I did start with an after market upper dash metal piece but it did not quite cover the area I needed to fix. I wish I had pictures of the repair as it went a lot easier then it sounds. The hardest part is finding that good donor! I have seen used dash faces ebay. Hope this helps, Dan
