74 duster dash removal

What Kern Dog said

You may have to pull the heater/ AC and likely the radio, and the glove box and cluster

I've done this on two cars, both 67, and both had the dash frame partially gutted, as mentioned

Get a small die grinder with a cut-off wheel and you can cut the sheet metal clips into which the screws go, and release the dash. You can install new clips upside down, and put new screws back in from the bottom. I think I used longer screws to get things started, then shorter screws as I started to draw things up. You want to be careful about screw length as they can damage the gasket, and for all I know, may damage the windshield as well