: Varies with RPM to ensure full coil saturation
Ford's and Duraspark II systems differ primarily in their electrical performance and availability. While Duraspark II (DS2) is the more common "standard" system, Duraspark I (DS1) is often cited as the most powerful factory ignition Ford produced for carbureted engines . Key Technical Differences Duraspark I (DS1) Duraspark II (DS2) Primary Region California-only (emissions compliance) 49-state (standard version) Grommet Color Red plastic insert at the wire leads Blue (most common), though other colors exist Dwell Control ford-duraspark-1-vs-duraspark-2
: Simpler design with less consistent high-RPM performance Resistor Wire No resistor wire; runs on full battery voltage : Varies with RPM to ensure full coil