This just happend to me with the original points system, if this is the system you run trust me on this,replace everything! dont even bother with the process of elimination, it will drive you crazy! the goods are fairly inexpensive, cap,rotor,wires,plugs,condensor,coil and for sure the points, trust me change it all regardless of how clean it looks. Make sure you have an accurate dwell meter, it is a very simple system and shouldnt be any reason for no spark.