Maybe your young and it is way before your time but I worked on some English cars before and the positive side of the battery hooked to the chassis like a ground cable.

 

I'm not that young but the oldest car that i've had was a 1970 Ford Capri 3.0ltr GT back in the early 80's with earth cable to the chassis, not being that mechanicly minded i get most of my work done at a garage but as they say it's never to late to learn. I've had GM cars now for the past 17 years and when they go wrong they have to be plugged in to a computor

 

The Brits gave up on positive ground a long time ago. Was interesting trying to jump start those old cars.

 

I bet it was, but it's before my time, but haveing said that it was plugs and points when i started driveing not electronic ignition