Accel's engineers have designed a new ultra high performance ignition module to overcome the problems and shortcomings of most OE and aftermarket GM HEI 4-pin modules. Modified dwell circuitry draws sufficient amperage to insure full coil saturation up to 9,000 RPM. This eliminates the high RPM miss due to lack of sufficient spark energy output. While other designs have used hand-placed and soldered components, this completely new design utilizes the latest surface mount electronic technology to maximize efficiency, output and reliability while minimizing size and problems with vibration and heat buildup.Requires no wiring harness or distributor modifications and is a direct plug-in replacement for all GM and aftermarket 4-pin HEI modules.