Quartz car clock
Strange thing about quartezed car clocks, after the conversion, you would think the second hand would "jump" like it does on a home battery quartz clock, but NO, it sweeps around like a home AC powered clock. In a car, one would WANT the second hand to jump or appearance sake. Fortunately, some cars, like the '55 Caddy, don't have second hands, so noone would know it had been converted.
There are people out there now that have perfected electronic substitures for the vibrator section of old car radios (apparently even NOS vibrators didn't age well) and FM conversions that look totally original.