PERTRONIX 91181LS IGNITOR® II DELCO 8 CYL ELECTRONIC IGNITION CONVERSION KIT 91181LS 12-Volt Negative Ground Adaptive dwell maintains peak energy throughout the entire RPM range, reducing misfires while improving engine performance. Develops on average 4 times more available energy between 3000 and 5000 RPM, and 2 times more available plug voltage. Compensates for inherent electronic delay by adjusting the spark timing throughout the entire RPM range. Synchronized peak current and spark timing reduces heat build-up. Senses startup and develops more energy for quicker, easier starting. Pair with a Flame Thrower Canister Coil for optimal performance