I'm stuck on the spark at the right time as being a strong contender so maybe go back to Hotrods recommendation on timing. Also, regarding the coil and ballast resistor discussion. You could "jump" around the ballast resistor to see if 12v on the coil helped the spark but since you said it has good spark now, I'm leaning towards the timing issue. Question, the engine was running before you pulled the head, right? So when you rebuilt the head did you remove , disconnect or replace anything within the ignition or fuel system?
