Brad Allen,
It sounds like you are going for the stock appearance. My book shows a Delco regulator #1118517. This is a 12 volt, negative ground regulator that's adjusted to a max output of 55 amps. I searched the web and came up empty, so I don't know if the number is still good.
Wouldn't some of the specialty suppliers have a 12 volt regulator for just this swap. Have you checked the 'Links' section.
Stuart
