If you haven't already done it, check your actual speed with a GPS unit. Your speedometer may not be accurate. Does your engine have a slight ping when its in one gear too low, as in, under a load? If not, you may get better performance if you advance the timing until it does ping slightly under load. I advance my timing until it pings, then retard it a smidge. I just don't like to here that pinging. Some will say to time it at idle so that the ball is on the needle and you are good to go. I differ from that suggestion due the many variables that affect timing once the the gas pedal is pushed. They include, somewhat worn mechanical advance, point gap not perfect due to slight error or normal wear, and vacuum advance pivot rivet wear. When all of these components are set perfectly and are brand new, then ball on needle is likely the correct setting for best all around performance. For real world conditions it may only represent a good place to start IMHO. (See? I can be humble).
Carl
