Dash pad is held it by some speed nut located on the back side. Its a pain in the *** but you have to get under and behind the dash to get to them.
I had to take my glove box and ash tray compartments out to get to the ones on the passenger side and the drivers side u might be able to just reach up in there and get to them through everything although it might be easier to remove your speedometer and get them that way.
It's been awhile since ive done it so i dont remember how many nuts hold it in place total but it was a real pain in the butt.
I just took the one off my 68. I was stripping the entire dash apart anyways so it made it easier. There were about 8 or so nuts under the dash that need to come off. If you can get the guage cluster out of the way and take off the glove box, it will make things way easier, otherwise you will have to reach from underneath to the bottom of the dash pad to get to the nuts. Also it will make it easier to actually see the nuts when trying to locate them.