another total timing question

Some of the stock distributors had as much as 30* of advance built into them (they would be stamped 15).

Here's an article the covers how to recurve the distributor, but the plate FBO makes is by far the better way to go. Most of the info in the article is in the text with the pictures, not the body of the article.

http://www.hotrod.com/how-to/engine/mopp-0301-mopar-electronic-ignition-system/