Harm from reversed polarity?

[SMB]

I have a friend with a 37 ford with the flathead.   The 6 volt  battery has been installed with a negative ground rather than the factory positive ground configuration.   His amp meter is naturally reversed.   He says it is running and so is reluctant to change the polarity.

My question is:  What harm would it possibly do to the electrical components of the car?  I know the starter and light bulbs will function but what about the generator he just replaced, coil, voltage regulator, etc.? 

Thanks,

Edited August 31, 2015 by SMB (see edit history)

[CarlLaFong]

No harm. Just switch the cables and re polarize the generator

[JWLawrence]

In addition to the amp meter leads and repolarzing the generator, the leads on the coil will need to be reversed too, if the system is negatively grounded. Why not restore the positive ground? It functions perfectly in this configuration. There is no advantage to having negative grounded electrical system.

 

(o{}o)

[Curti]

I believe a radio will be damaged  if the polarity is reversed. If there is a radio, hopefully he has not turned it on.

[MikeC5]

Something to consider: if it doesn't have a radio there are advantages to leaving it negative ground.  If he tours with it, having 12V DC negative ground (assuming it is 12V) lets you power things like a GPS or anything that you might want to charge while driving.  If he decides to leave it negative ground, the terminals on the coil should maybe be switched because otherwise it may have an adverse effect on the points.

[CarlLaFong]

^^^^^^^Stock 37 Ford is 6 volts^^^^^^