On a 70 the coil (+) wire should be getting voltage in the START posistion without the yellow attached to solenoid "S" terminal. Check to see if it is when you are cranking the car.
Others have stated that the bump voltage is not needed with modern coils.
http://www.chevelles.com/cgi-bin/forum/ultimatebb.cgi?ubb=get_topic;f=22;t=002489
Others have stated that the bump voltage is not needed with modern coils.
http://www.chevelles.com/cgi-bin/forum/ultimatebb.cgi?ubb=get_topic;f=22;t=002489