[rotorwrench]

Magnetos are not really good for a street car. They have to be set up for full advance on most applications and they have to have an impulse coupling to get them to start without damaging the starter unless a person can set them up for a manual advance that moves the whole unit for timing. Vertex/Scintilla does have an internal mechanical advance but it has to move the whole system internally so that the internal timing will not be off of the E-gap. This is one of the reasons that they are so big. There is no vacuum control retard system for any magneto that I've ever come across.