Back in the 50's a LOT of English cars (and perhaps others) were positive ground systems, many of them 6 volt at that. Positive ground 'didn't catch on' because most everybody in the world was using negative ground.
I would assume from that a (EDIT: "typo" I first said positive, but I mean...) NEGATIVE ground system works better, unless of course your pretty sure Lucas Wiring was onto something. Lucas? Had a better idea? Not likely!
This is complicated enough without screwing up positive and negative when your typing!
