Have read thru numerous posts on this topic. I get the vacuum advance theory but what is out on the internet seems to be a bit vague when it comes to to figuring out the mechanical advance settings or what total timing really is. So example my mechanical all in dist set and locked at 28 degrees advanced all in but am idling at 16 degrees advanced what is my total advance when running all in? So no matter how i set the idle advance i end up with 28 degrees so 10 advanced at all in still times out to 28 and 20 advanced still times out to 28. Have seen a number of calculations that spell this out so just looking so is is my total timing 28 degrees with a mechanical advance of 8 degrees 28-20 = 8 or is it 28 total? or is it 28 + 20 for a total of 48 degrees. Not the best question but just looking to understand this.