The first one I did was with the dash frame in place in the car. It was pretty hard to get to all the stamped nuts to get it off. I don't think I got them all back on because it is so tight.

The second one I did was out of the caR AND IS THE ONLY WAY i WOULD DO IT AGAIN.
Windsheild does not have to come out to remove the dash assembly.

I clamped mine to a homemade T support that I use for my miter saw to support wood when cutting. Used a visegrip to clamp it on.

Where's there's a will there is a way. I built and assembled this whole car by myself, everything you see in my pictures, everything by myself!