The same with counting battery caps. American cars went to 12 volts across the board by 1956. VW by 1968. I'm not sure when negative grounding became standard. At least most thermostats have jiggle valves now and I don't have to drill them.

 

Now you guys are making me feel like an "old timer" even that it may be true. I confused a new hire by showing him a drag link socket, He never seen one before.

 

I don't do work for other people anymore, but I have helped local guys I know work on their brakes. Especially 1964 and earlier Mopar brakes. Sometimes it's an understanding of mechanical processes rather than computer savvy to find a problem. I've got an old Furd truck that pulled 15 inches of vaccum when running when I got it. It started running worse and was pulling 10 inches of vacuum. Now it won't start. I'll be taking a hammer and piece of pipe to the exhaust and clean the catalytic converters out. I'm pretty sure the exhaust is stopped up.