my understanding is generally pertronix is used in the older SCV environment, and as such has no mechanical advance and is less desirable than the DS2.I suppose its possible to augment a 68 or later points carb that has mech advance, but no installs stand out. I've also heard of the sensor/magnet/whatever coming loose, but I don't know if that's user error, random issues, or product feature. The squeaky wheel and all that.