Technical Wiring Help

[luigirox]

So I am starting to put my car back together
Fiat 500r 1975. I noticed that it was setup for positive ground and ignition coil was wired with the positive end to the chassis. I think it has dynomo and not alternator. It has a regulator on the firewall.

Questions
Why would it be setup for positive ground?
If I switch it to negative ground do I have to change something with the dynomo?
I am just good with switching the coil over to negative to the chassis.
I attached some pictures

 

[bugsymike]

So I am starting to put my car back together
Fiat 500r 1975. I noticed that it was setup for positive ground and ignition coil was wired with the positive end to the chassis. I think it has dynomo and not alternator. It has a regulator on the firewall.

Questions
Why would it be setup for positive ground?
If I switch it to negative ground do I have to change something with the dynomo?
I am just good with switching the coil over to negative to the chassis.
I attached some pictures

Others may have more advice, but personally I am of the "if it ain't broke don't fix it brigade" regarding this. Basically if you want to run an alternator which has benefits in higher better regulated output etc. then you have to run Negative earth as that is the way they are designed.
But dynamo systems are generally Positive earth, although I believe I read somewhere that they can be set to run Negative earth by flashing the field winding terminal, but read up about it first and like the coil and possibly the radio and other things you will need to change that, so don't just dive in!