Hey Jeff,
The answer is pretty easy...
Teh "Total Advance" is the sum(additive) of the your intial timing-
ex. for a 390 is 6BTDC take that plus your total amount of centrifugal advance. - The maximum you can get from your distributor.
ex. 6 degrees BTDC + 26 degrees centrifugal = 32 degrees total advance.
check out this article:
http://www.fordmuscle.com/archives/2...ng/index.shtml
very helpful!!
- mac