Voltage regulator specification

[fordfun]

The 1929 Sports Coupe I acquired last year appears to have a later model generator. The unit seems to be functioning acceptably, however I would like to add a voltage regulator. I understand that an EVR may need to be matched to the generator, and at this point I'm not sure which generator I have. It's approximately 5.75" long with a 1.5" wide band. I'm running a 6v positive ground system. Any help you can give me in determining the type of generator I have will be greatly appreciated. (Photos attached).

I would also appreciate any recommendations you have regarding a source for the correct EVR.

Thanks - Bill