FYI, your clock. I'm assuming it is 6 volt? And is you car 6v Or 12v conversion?
You might check in Hemmings.
I have found it is tough to get an analog clock to keep decent time. I tried many different methods to get one to operate. I also tried quartz conversion but didn't like it because of its action, analog old school is more fun, just like vacuum windshield wipers!
Mine (6 v) runs fine (with 2 resistors) on a 12v system.
However, it is totally unacceptable as a clock! I have finally quit obsessing with it and am just content to have it running with a sweep second hand. If I really care about accurate time, I look at my iphone! Just my 2 cents.
A L A N F R A K E S ~ Tulsa, OK