I see lots of you have read my Demon Tuning 101 article, have you read the Mission Ignition article?
http://www.4secondsflat.com/Mission%2520Ignition.html
Study the chart at the bottom od the page, it may help you understand your performance engine and how the changes you make affect the timing issues.
One more note...42-46-48 total timing????I've never heard of such numbers on a Unleaded low octane motor??
Unless the combination is so poor that it needs that much lead to make it run...I just don't believe that that motor makes max HP at those numbers.
We used to set our SB Chebby Alcohol injected 8000 RPM Sprint Car motors at 42* on a Mag, but on a street car I'd have to see that to believe it.
Send me a spark plug I want to look at it.
I don't claim to be an Ford engine master and I'm the first to admit it, give me a boring machinme and you might as well of given me a file.
But with my 35 Years of experience in tuning ignition and carburetion I wish engine builders would admit that they aren't tuners, and consult with someone that is before they build these wild combinations...you just wouldn't believe what I run into, some stuff I just refuse to work on it's so far from reality that no carb and no amount of ignition tuning will ever make it run in the application intended.
I work with several builders and cam grinders and we always discuss my end with there idea's before the grinder gets put to the steel....final result is a perfect combination well within the capability's of the owner.