I think you need to take a deep breath and approach this from a diagnostic standpoint. Put a vacuum gauge on it. What is the reading at idle hot? WHERE is the initial timing set? WHERE is the total timing? Plot that curve in a graph and look at it. A stock slant should have close to or over 20hg of vacuum. If it doesn't something's wrong. That car should be knocking down 20 plus MPG, IMO being driven conservatively.