If i remember well you must NOT use a "performance coil" (as mallory or other brands) with the Pertronix (except the "Flame-thrower" performance coils, sold by Pertronix ..). I read this on the instructions of the unit. If the unit failed you lost the warranty. Pertronix web site: http://www.pertronix.com/ignition/index.htm -- Philippe COURANT (Pau, France) Imperial 57 Crown convertible Buick 58 Roadmaster sedan - American Car Club de France (ACCF) : http://www.accf.com - Chrysler Imperial France : http://www.ifrance.com/c-i-f - Cadillac " Standard of Excellence " : http://www.ifrance.com/accf-cad - SportsCars : http://www.ifrance.com/accf-sprtcar