In addition to the circumferential Rotor Phasing air gap distance there is also the radial rotor tip to cap terminal gap which is ideally should be brought down to ~.015" either by drilling out the rotor blade rivet & subbing in a longer piece of brass or Echlin offers a rotor with a .060" longer blade, an Echlin MO3000 for $8.xx out the door which helps. You want the gaps to be as MINIMAL as possible (without contact/interference obviously) & more gap=more sparking & smaller gap=less sparking & more gap increases the required voltage to jump said gap & is a waste of energy/stresses the coil/ign system & if the required voltage exceeds the available voltage from your choice of parts it will misfire. Also dremel the rotor tip/cap terminals being carefull not to remove hardly any brass as it takes less voltage to jump from sharp terminals to sharp terminals than it does rounded ones (from wear).