Wondering how the clock is removed on a 57 Star Chief?

On the back of the clock is a u shaped bracket that is held on with two very small nuts. The clock has two small studs that go through holes in the bracket. Get underneath the dash and with a small wrench ( I forget the size) remove the two nuts and the u shaped bracket, then the clock pulls out from the front of the dash. It is a snug fit, so you may have to push it out from the back of the clock.  My 57 Pontiac is a Canadian built car but your clock should be the same. Good luck and cheers.

1 hour ago, Longstroke said:

On the back of the clock is a u shaped bracket that is held on with two very small nuts. The clock has two small studs that go through holes in the bracket. Get underneath the dash and with a small wrench ( I forget the size) remove the two nuts and the u shaped bracket, then the clock pulls out from the front of the dash. It is a snug fit, so you may have to push it out from the back of the clock.  My 57 Pontiac is a Canadian built car but your clock should be the same. Good luck and cheers.

bet they are 1/4 inch !

My US built Star Chief has the clock held in by the U shaped bracket, which is contained by a wing type nut that screws onto a single stud in the centre of the clock.

Russell, thanks for the clarification. Looks like my Canadian clock in my 57 Pontiac is different. Cheers.