The clock in my '70 Chevelle SS doesn't work. What's the procedure for removing the dash to get it out. Has anyone replaced the movement with a quartz one with the clock still in the car. I heard it can be done but it doesn't look like it to me. Any help will be greatly appreciated.

Pull the dash pad off (4-6 screws?), then pull off the whole gauge cluster (good luck finding all the little screws, probably 8 or so) to get to just the clock. It's typically easier to loosen the dash up, lower the steering column, etc just to be able to get your hands back there.

Job is not really that bad - just look for the attachments and undo them - but while you're back there you may want to replace all the little bulbs.