Here's a couple places that specialize in this: http://www.autoinstruments.com/ http://dandmrestoration.home.mindspring.com/ http://www.tachman.com/main.htm
Board member here Patsusedparts does them, has some in stock and he has gotten good feedback. i know him and he is a good person to deal with.
i had the clock in my 72 gs rebuilt with a quartz movement by a company in farmington mi. the strangest thing is this. when i remove the battery (winter storage) and reconnect a month later just to start, run and move the car for several minutes, the clock may or may not work. the past couple of years, in spring , april , when i remove my car from storage to begin driving it , it usually takes a couple of days before the clock will work constantly. i believe that i have a summer only clock!!
