I am in the process of replacing the dash in my '51. The previous owner had cut out the bottom of the dash to insert some Ford controls. I used a spotweld cutter for the spotwelds by the window. There are also a bunch of spotwelds in places you can't get to...like on the sides of the dash by the doors. For those, I had to work a chisel between the dash metal and the metal it was welded to. I hammered a little bit, and voila! I got it out. All that was on the donor truck.
On the truck I am fixing, I used a Dremel with heavy duty cut-off wheels and just cut around the edges and left the spotwelds in place. When the dash was out, I ground around all of the spotwelds. It's a lot of time and work, but I know I will be satisfied when I am done.
